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Sample records for catheter ablation predicts

  1. 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.

  2. Prediction of Primary Slow-Pathway Ablation Success Rate according to the Characteristics of Junctional Rhythm Developed during the Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia

    PubMed Central

    Bagherzadeh, Ataallah; Rezaee, Mohammad Esmaeel; Farahani, Maryam Moshkani

    2011-01-01

    Background Nowadays, developed junctional rhythm (JR) that occurs during slow-pathway radiofrequency (RF) catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) has been focused upon as a highly sensitive surrogate end point for successful radiofrequency ablation. This study was conducted to assess the relationship between the presence and pattern of developed JR during the RF ablation of AVNRT and a successful outcome. Methods Seventy-five patients aged between 14 and 88 who underwent slow-pathway RF ablation due to symptomatic AVNRT were enrolled into the study and received a total of 162 RF energy applications. Combined anatomic and electrogram mapping approach was used for slow-pathway RF ablation. The ablation procedure consisted of 60-second, 60 °C temperature-controlled energy delivery. After each ablation pulse, successful ablation was assessed according to the loss of AVNRT inducibility via isoproterenol infusion. Four different patterns were considered for the developed JR, namely sparse, intermittent, continuous, and transient block. Success ablation rate was assessed with respect to the position, pattern, and number of junctional beats. Results Successful RF ablation with a loss of AVNRT inducibility was achieved in 43 (57.3%) patients using 119 RF energy applications (73.5%). JR developed in 133 of the 162 (82.1%) applications with a given sensitivity of 90.8% and low specificity of 41.9% as an end point of successful RF ablation, with a negative predictive value of 62.1%. The mean number of the developed junctional beats was significantly higher in the successful ablations (p value < 0.001), and the ROC analysis revealed that the best cut-off point of the cumulative junctional beats for identifying accurate AVNRT ablation therapy is 14 beats with 90.76 % sensitivity and 90.70% specificity. There were no significant differences in terms of successful ablation rates according to the four different patterns of JR and its positions (p

  3. Distal end of the atrioventricular nodal artery predicts the risk of atrioventricular block during slow pathway catheter ablation of atrioventricular nodal re-entrant tachycardia

    PubMed Central

    Lin, J; Huang, S; Lai, L; Lin, L; Chen, J; Tseng, Y; Lien, W

    2000-01-01

    OBJECTIVE—To search for a reliable anatomical landmark within Koch's triangle to predict the risk of atrioventricular (AV) block during radiofrequency slow pathway catheter ablation of AV nodal re-entrant tachycardia (AVNRT).
PATIENTS AND METHODS—To test the hypothesis that the distal end of the AV nodal artery represents the anatomical location of the AV node, and thus could be a useful landmark for predicting the risk of AV block, 128 consecutive patients with AVNRT receiving slow pathway catheter ablation were prospectively studied in two phases. In phase I (77 patients), angiographic demonstration of the AV nodal artery and its ending was performed at the end of the ablation procedure, whereas in the subsequent phase II study (51 patients), the angiography was performed immediately before catheter ablation to assess the value of identifying this new landmark in reducing the risk of AV block. Multiple electrophysiologic and anatomical parameters were analysed. The former included the atrial activation sequence between the His bundle recording site (HBE) and the coronary sinus orifice or the catheter ablation site, either during AVNRT or during sinus rhythm. The latter included the spatial distances between the distal end of the AV nodal artery and the HBE and the final catheter ablation site, and the distance between the HBE and the tricuspid border at the coronary sinus orifice floor.
RESULTS—In phase I, nine of the 77 patients had complications of transient (seven patients) or permanent (two patients) complete AV block during stepwise, anatomy guided slow pathway catheter ablation. These nine patients had a wider distance between the HBE and the distal end of the AV nodal artery, and a closer approximation of the catheter ablation site to the distal end of the AV nodal artery, which independently predicted the risk of AV block. In contrast, none of the available electrophysiologic parameters were shown to be reliable. When the distance between

  4. Catheter ablation of parahisian premature ventricular complex.

    PubMed

    Kim, Jun; Kim, Jeong Su; Park, Yong Hyun; Kim, June Hong; Chun, Kook Jin

    2011-12-01

    Catheter ablation is performed in selected patients with a symptomatic premature ventricular complex (PVC) or PVC-induced cardiomyopathy. Ablation of PVC from the His region has a high risk of inducing a complete atrioventricular block. Here we report successful catheter ablation of a parahisian PVC in a 63-year-old man.

  5. Empirical mode decomposition of multiple ECG leads for catheter ablation long-term outcome prediction in persistent atrial fibrillation.

    PubMed

    Hidalgo-Munoz, Antonio R; Tome, Ana M; Latcu, Decebal G; Zarzoso, Vicente

    2015-01-01

    Predictive models arouse increasing interest in clinical practice, not only to improve successful intervention rates but also to extract information of diverse physiological disorders. This is the case of persistent atrial fibrillation (AF), the most common cardiac arrhythmia in adults. Currently, catheter ablation (CA) is one of the preferred therapies to face this disease. However, selecting the best responders to CA by standard noninvasive techniques such as the electrocardiogram (ECG) remains a challenge. This work presents different predictive models for determining long-term CA outcome based on the dominant frequency (DF) of atrial activity measured in the ECG. The ensemble empirical mode decomposition (EEMD) is employed to obtain the intrinsic mode functions (IMFs) composing the ECG signal in each lead. The IMF DFs computed in multiple leads are then combined into a logistic regression (LR) model. The IMF DF features are discriminant enough to reach 79% accuracy for long-term CA outcome prediction, outperforming other methods based on DF computation. Our study shows EEMD as a valuable alternative to extract clinically relevant spectral information from AF ECGs and confirms the advantage of LR to build multivariate predictive models as compared with univariate analysis.

  6. 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

  7. 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.

  8. Robotic navigation for catheter ablation: benefits and challenges.

    PubMed

    Aagaard, Philip; Natale, Andrea; Di Biase, Luigi

    2015-07-01

    Manual radio frequency (RF) ablation to restore a normal cardiac rhythm requires significant skill, manual dexterity and experience. In response to this, ablation methods and technologies have evolved rapidly in the past decade, including the development of remote navigation technologies. Today, two principal methods of remote navigation are available. One utilizes magnetic field vectors to navigate proprietary catheters, the other maneuvers standard catheters robotically. The main advantages of remote navigation include improved catheter stability, reduced fluoroscopy times and decreased total radiation exposure to both the patient and the operator. The main limitations include cost and longer procedure times. Remote magnetic navigation appears to have the best safety profile; however, its efficacy in creating lesions may be lower, which has been attributed to the soft-tip catheter used. Remote robotic navigation on the other hand, which uses regular catheter tips, is associated with a slightly higher overall complication rate, but higher efficacy. This article reviews the pros and cons of remote navigation for ablation of both atrial and ventricular substrates. Finally, it attempts to predict the direction of this field in the coming years.

  9. Catheter microwave ablation therapy for cardiac arrhythmias.

    PubMed

    Lin, J C

    1999-01-01

    This article describes three microwave catheter antennas for percutaneous cardiac ablation. A particular design feature of these antennas is that there is no reflected microwave current from the antenna flowing up the transmission line. Thus, it minimizes heating of the coaxial cable. The power reflection coefficients are very low (4% or less) in phantom equivalent materials. These antennas can also serve as bipolar electrodes for sensing endocardiac electrograms. Our studies in dogs, during both cardiopulmonary bypass and closed-chest operations via the femoral vein, have shown microwave energy greater than 200 joules (J) delivered to the heart through a split-tip dipole catheter antenna can produce irreversible block of the heart rhythms. This energy was achieved either by increasing the delivered power from 20 to 40 watts or by increasing the treatment duration from 7 to 11 s (210 to 330 J per application). It produced an endocardium temperature of about 65 degrees C. We found that the percutaneous, transcatheter microwave system is capable of inducing AV blocks consistently in dogs using the flexible, curved tip, split-tip catheter antenna. In addition, our studies have shown that the width and height of SAR distributions for cap-choke and split-tip catheter antennas are similar for the same antenna length. The cap-slot design had a much longer SAR distribution compared to the others. Moreover, a longer (4 mm) split-tip antenna can also induce larger lesions. These results suggest that it could be possible to ablate a ventricular tachycardia focus using the 4 mm split-tip as well as the cap-slot microwave catheter antennas. PMID:10334721

  10. Pulmonary Vein Stenosis Complicating Radiofrequency Catheter Ablation

    PubMed Central

    Lu, Hai-Wen; Wei, Ping; Jiang, Sen; Gu, Shu-yi; Fan, Li-Chao; liang, Shuo; Ji, Xiaobin; Rajbanshi, Bhavana; Xu, Jin-Fu

    2015-01-01

    Abstract The aim of this study is to characterize the clinical manifestations and features of pulmonary vein stenosis (PVS) by retrospectively analyzing clinical data of patients in addition to reviewing the literature simultaneously to improve the understanding of PVS complicating radiofrequency catheter ablation and to provide evidence for early diagnosis and timely treatment. Clinical, imaging, and follow-up data of 5 patients with PVS-complicating radiofrequency catheter ablation were retrospectively analyzed between January 2012 and December 2014 in Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China. Relevant studies previously reported were also reviewed. Three out of 5 patients received pulmonary angiography. The initial symptoms were not specific, presenting chest pain in 3 cases, hemoptysis in 2 cases. The average duration between radiofrequency ablation to the onset of symptoms was 5.8 months. The chest image results were consolidation and pleural effusion mainly. Veins distributed in the left lungs were mostly influenced in 4 patients, and the inferior veins in 3 patients. Cardiac ultrasound examinations showed pulmonary arterial hypertension in 2 patients. Two patients received selective bronchial artery embolization after bronchial artery radiography because of hemoptysis. One patient underwent video-assisted thoracoscopic biopsy because of the suspicion of tumor. PVS is a condition mostly undetected because of its silent manifestations and inconsistent follow-up. The accurate clinical diagnosis is very difficult. A careful review of medical history and follow-up observation may be useful for all the patients who received the radiofrequency catheter ablation to recognize PVS in the early stage. PMID:26313772

  11. Ultrasound catheters for circumferential cardiac ablation

    NASA Astrophysics Data System (ADS)

    Diederich, Chris J.; Nau, William H.; Taylor, Kevin; Maguire, Mark T.; Picazo, Guillermo; Gangu, Madhuri; Lesh, Michael D.

    1999-05-01

    The purpose of this study was to investigate performance characteristics of a catheter-based ultrasound applicator intended for circumferential ablation of cardiac tissue. The catheter design integrates a cylindrical ultrasound transducer within a distendable water filled balloon in order to produce circumferential lesions at sites in the atria (i.e., pulmonary vein ostia), intended for treatment of certain atrial arrhythmias. Biothermal simulations were used to investigate thermal lesion depths corresponding to variations in applied power, duration, balloon diameter, and acoustic efficiency. Prototype applicators of varying frequency (7 - 12 MHz) and balloon diameter were constructed and characterized using measurements of acoustic efficiency and rotational beam plots. In vitro studies were performed in freshly excised beef hearts to characterize the radial penetration, axial length, and angular uniformity of thermal lesions produced by these applicators. Selected applicators were tested in vivo within pulmonary veins, coronary sinus, and atrial appendage of canine and porcine hearts. These preliminary efforts have indicated that circumferential ablation of cardiac tissue using ultrasound balloon catheters is feasible, and devices between 7 - 12 MHz with balloon diameters of 1.5 - 2.0 cm are capable of producing uniform lesions between 1 - 5 mm depth or greater for treatment durations of 120 seconds or less.

  12. The use of radiofrequency catheter ablation to cure dilated cardiomyopathy.

    PubMed

    Schmidt, S B; Lobban, J H; Reddy, S; Hoelper, M; Palmer, D L

    1997-01-01

    Incessant supraventricular tachycardia can cause a dilated cardiomyopathy. This article discusses the case of a 55-year-old woman whose cardiomyopathy was reversed when she underwent successful radiofrequency catheter ablation of a unifocal atrial tachycardia. PMID:9197188

  13. The effect of elastic modulus on ablation catheter contact area

    NASA Astrophysics Data System (ADS)

    Camp, Jon J.; Linte, Cristian A.; Rettmann, Maryam E.; Sun, Deyu; Packer, Douglas L.; Robb, Richard A.; Holmes, David R.

    2015-03-01

    Cardiac ablation consists of navigating a catheter into the heart and delivering RF energy to electrically isolate tissue regions that generate or propagate arrhythmia. Besides the challenges of accurate and precise targeting of the arrhythmic sites within the beating heart, limited information is currently available to the cardiologist regarding intricate electrodetissue contact, which directly impacts the quality of produced lesions. Recent advances in ablation catheter design provide intra-procedural estimates of tissue-catheter contact force, but the most direct indicator of lesion quality for any particular energy level and duration is the tissue-catheter contact area, and that is a function of not only force, but catheter pose and material elasticity as well. In this experiment, we have employed real-time ultrasound (US) imaging to determine the complete interaction between the ablation electrode and tissue to accurately estimate contact, which will help to better understand the effect of catheter pose and position relative to the tissue. By simultaneously recording tracked position, force reading and US image of the ablation catheter, the differing material properties of polyvinyl alcohol cryogel[1] phantoms are shown to produce varying amounts of tissue depression and contact area (implying varying lesion quality) for equivalent force readings. We have shown that the elastic modulus significantly affects the surface-contact area between the catheter and tissue at any level of contact force. Thus we provide evidence that a prescribed level of catheter force may not always provide sufficient contact area to produce an effective ablation lesion in the prescribed ablation time.

  14. 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

  15. Conservative Management of Left Atrial Intramural Hematoma after Catheter Ablation

    PubMed Central

    Oraii, Saeed; Roshanali, Farideh; Ghorbanisharif, Alireza; Mikaeili, Javad; Tahraei, Mahmood

    2016-01-01

    Left atrial intramural hematoma is a very rare complication of radiofrequency ablation procedures. A patient with tachyarrhythmia underwent radiofrequency catheter ablation. Echocardiography performed the following morning showed a large mass in the left atrium, suggestive of intramural hematoma formation. The patient was in a stable condition; therefore, it was decided that follow-up should be conservative and her anticoagulation therapy was continued. The size of the hematoma decreased significantly over the following 50 days. This case highlights a rare complication of a complex catheter ablation procedure in the left atrium that was managed via a noninvasive approach, with which all interventionists should be familiar. PMID:27482270

  16. Novel catheter enabling simultaneous radiofrequency ablation and optical coherence reflectometry

    PubMed Central

    Herranz, D.; Lloret, Juan; Jiménez-Valero, Santiago; Rubio-Guivernau, J. L.; Margallo-Balbás, Eduardo

    2015-01-01

    A novel radiofrequency ablation catheter has been developed with integrated custom designed optics, enabling real-time monitoring of radiofrequency ablation procedures through polarization-sensitive optical coherence reflectometry. The optics allow for proper tissue illumination through a view-port machined in the catheter tip, thus providing lesion depth control over the RF ablation treatment. The system was verified in an in-vitro model of swine myocardium. Optical performance and thermal stability was confirmed after more than 25 procedures, without any damage to the optical assembly induced by thermal stress or material degradation. The use of this catheter in RF ablation treatments may make possible to assess lesion depth during therapy, thus translating into a reduction of potential complications on the procedure. PMID:26417499

  17. A systematic review of surgical ablation versus catheter ablation for atrial fibrillation

    PubMed Central

    Kearney, Katherine; Stephenson, Rowan; Phan, Kevin; Chan, Wei Yen; Huang, Min Yin

    2014-01-01

    Background Atrial fibrillation (AF) is an increasingly prevalent condition in the ageing population, with significantly associated morbidity and mortality. Surgical and catheter ablative strategies both aim to reduce mortality and morbidity through freedom from AF. This review consolidates all currently available comparative data to evaluate these two interventions. Methods A systematic search was conducted across MEDLINE, PubMed, Embase, Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews from January 2000 until August 2013. All studies were critically appraised and only those directly comparing surgical and catheter ablation were included. Results Seven studies were deemed suitable for analysis according to the inclusion criteria. Freedom from AF was significantly higher in the surgical ablation group versus the catheter ablation group at 6-month, 12-month and study endpoint follow-up periods. Subgroup analysis demonstrated similar trends, with higher freedom from AF in the surgical ablation group for paroxysmal AF patients. The incidence of pacemaker implantation was higher, while no difference in stroke or cardiac tamponade was demonstrated for the surgical versus catheter ablation groups. Conclusions Current evidence suggests that epicardial ablative strategies are associated with higher freedom from AF, higher pacemaker implantation rates and comparable neurological complications and cardiac tamponade incidence to catheter ablative treatment. Other complications and risks were poorly reported, which warrants further randomized controlled trials (RCTs) of adequate power and follow-up duration. PMID:24516794

  18. 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

  19. Idiopathic ventricular tachycardia: feasibility and efficacy of catheter ablation.

    PubMed

    Velazquez Rodriguez, E; Frank, R; Fontaine, G; Tonet, J; Lascault, G; Rosas, F; Eslami, M; Nakazato, Y

    1995-01-01

    Idiopathic ventricular tachycardia is a well described syndrome of both left and right ventricular origin. This study reports the feasibility and efficacy of catheter ablation in this entity. Fourteen patients (mean age 30 +/- 10 years of age) and six patients (mean age 51 +/- 9 years of age) underwent endocardial catheter ablation with either direct-current shocks and radiofrequency energy, respectively. Earliest right and left ventricular activation and endocardial mapping during tachycardia were made to localize the site of ventricular tachycardia origin. The overall clinical efficacy was 93% for direct-current method with a mean number of shocks of 3.3 +/- 0.9/patient after a mean follow-up of 38 +/- 25 months. Radiofrequency ablation achieved an overall clinical efficacy of 83.6% with a mean of 3.2 pulses/patient during a follow-up of 10.5 +/- 4 months. The isoenzyme MB fraction of peak creatine kinase after ablation was less than 5%. There were no complications in any patient who underwent radiofrequency energy. Endocardial catheter ablation is feasible in patients with idiopathic ventricular tachycardia. Both methods are highly effective but radiofrequency energy is most desirable because of its lack of barotrauma, and may be considered as early therapy. PMID:7620280

  20. Catheter ablation of atrial fibrillation in the elderly

    PubMed Central

    Lioni, Louiza; Letsas, Konstantinos P.; Efremidis, Michael; Vlachos, Konstantinos; Giannopoulos, Georgios; Kareliotis, Vasileios; Deftereos, Spyridon; Sideris, Antonios

    2014-01-01

    Background Atrial fibrillation (AF) catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly population. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were ≥ 65 years (48 males, mean age 68.9 ± 3.0 years old) and 221 patients were < 65 years old (130 males, mean age 52.5 ± 10.4 years old). After a mean follow-up period of 34.0 ± 15.1 months, 55 (57.9%) patients in the elderly group were free from arrhythmia recurrence compared with 149 (67.4%) patients in the younger group (P = 0.169). Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter (P = 0.003), hypertension (P = 0.001), dyslipidemia (P = 0.039), and coronary artery disease (P = 0.018) were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF. PMID:25593577

  1. Association of Single Nucleotide Polymorphisms with Atrial Fibrillation and the Outcome after Catheter Ablation

    PubMed Central

    Hu, Yu-Feng; Wang, Hsueh-Hsiao; Yeh, Hung-I; Lee, Kun-Tai; Lin, Yenn-Jiang; Chang, Shih-Lin; Lo, Li-Wei; Tuan, Ta-Chuan; Li, Cheng-Hung; Chao, Tze-Fan; Chung, Fa-Po; Liao, Jo-Nan; Tang, Paul Wei Hua; Tsai, Wei-Chung; Chiou, Chuen-Wang; Chen, Shih-Ann

    2016-01-01

    Background The association of gene variants with atrial fibrillation (AF) type and the recurrence of AF after catheter ablation in Taiwan is still unclear. In this study, we aimed to investigate the relationships between gene variants, AF type, and the recurrence of AF. Methods In our investigation, we examined 383 consecutive patients with AF (61.9 ± 14.0 years; 63% men); of these 383 patients, 189 underwent catheter ablation for drug-refractory AF. Thereafter, the single nucleotide polymorphisms rs2200733, and rs7193343 were genotyped using real-time polymerase chain reaction. Results The rs7193343 variant was independently associated with non-paroxysmal AF (non-PAF). In the PAF group, the rs7193343 variant was independently associated with AF recurrence after catheter ablation. However, the rs2200733 variant was not associated with AF recurrence in this group. The combination of the rs7193343 and rs2200733 risk alleles was associated with a better predictive power in the PAF patients. In contrast, in the non-PAF group, the SNPs were not associated with recurrence. The rs7193343 and rs2200733 variants were not associated with different atrial voltage and activation times. Conclusions The rs7193343 variants were associated with AF recurrence after catheter ablation in PAF patients but not in non-PAF patients. The rs7193343 CC variant was independently associated with non-PAF. PMID:27713600

  2. Catheter Ablation for Long-Standing Persistent Atrial Fibrillation.

    PubMed

    Romero, Jorge; Gianni, Carola; Di Biase, Luigi; Natale, Andrea

    2015-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and represents a major burden to health care systems. Atrial fibrillation is associated with a 4- to 5-fold increased risk of thromboembolic stroke. The pulmonary veins have been identified as major sources of atrial triggers for AF. This is particularly true in patients with paroxysmal AF but not always the case for those with long-standing persistent AF (LSPAF), in which other locations for ectopic beats have been well recognized. Structures with foci triggering AF include the coronary sinus, the left atrial appendage (LAA), the superior vena cava, the crista terminalis, and the ligament of Marshall. More than 30 studies reporting results on radiofrequency ablation of LSPAF have been published to date. Most of these are observational studies with very different methodologies using different strategies. As a result, there has been remarkable variation in short- and long-term success, which suggests that the optimal ablation technique for LSPAF is still to be elucidated. In this review we discuss the different approaches to LSPAF catheter ablation, starting with pulmonary vein isolation (PVI) through ablation lines in different left atrial locations, the role of complex fractionated atrial electrograms, focal impulses and rotor modulation, autonomic modulation (ganglionated plexi), alcohol ablation, and the future of epicardial mapping and ablation for this arrhythmia. A stepwise ablation approach requires several key ablation techniques, such as meticulous PVI, linear ablation at the roof and mitral isthmus, electrogram-targeted ablation with particular attention to triggers in the coronary sinus and LAA, and discretionary right atrial ablation (superior vena cava, intercaval, or cavotricuspid isthmus lines). PMID:26306125

  3. Catheter Ablation for Long-Standing Persistent Atrial Fibrillation

    PubMed Central

    Romero, Jorge; Gianni, Carola; Di Biase, Luigi; Natale, Andrea

    2015-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and represents a major burden to health care systems. Atrial fibrillation is associated with a 4- to 5-fold increased risk of thromboembolic stroke. The pulmonary veins have been identified as major sources of atrial triggers for AF. This is particularly true in patients with paroxysmal AF but not always the case for those with long-standing persistent AF (LSPAF), in which other locations for ectopic beats have been well recognized. Structures with foci triggering AF include the coronary sinus, the left atrial appendage (LAA), the superior vena cava, the crista terminalis, and the ligament of Marshall. More than 30 studies reporting results on radiofrequency ablation of LSPAF have been published to date. Most of these are observational studies with very different methodologies using different strategies. As a result, there has been remarkable variation in short- and long-term success, which suggests that the optimal ablation technique for LSPAF is still to be elucidated. In this review we discuss the different approaches to LSPAF catheter ablation, starting with pulmonary vein isolation (PVI) through ablation lines in different left atrial locations, the role of complex fractionated atrial electrograms, focal impulses and rotor modulation, autonomic modulation (ganglionated plexi), alcohol ablation, and the future of epicardial mapping and ablation for this arrhythmia. A stepwise ablation approach requires several key ablation techniques, such as meticulous PVI, linear ablation at the roof and mitral isthmus, electrogram-targeted ablation with particular attention to triggers in the coronary sinus and LAA, and discretionary right atrial ablation (superior vena cava, intercaval, or cavotricuspid isthmus lines). PMID:26306125

  4. Catheter Ablation of Multiple Accessory Pathways in Duchenne Muscular Dystrophy

    PubMed Central

    Stöllberger, Claudia; Steger, Christine; Gatterer, Edmund

    2013-01-01

    A 23-year-old male with Duchenne muscular dystrophy (DMD) experienced self-limiting palpitations at age 19 years for the first time. Palpitations recurred not earlier than at age 23 years, and were attributed to narrow complex tachycardia, which could be terminated with adenosine. Since electrocardiography showed a delta-wave, Wolff-Parkinson-White (WPW) syndrome was diagnosed, ajmaline prescribed and radio-frequency catheter ablation of three accessory pathways carried out one week later. One day after ablation, however, a relapse of the supraventricular tachycardia occurred and was terminated with ajmaline. Re-entry tachycardia occurred a second time six days after ablation, and as before, it was stopped only with ajmaline. Despite administration of verapamil to prevent tachycardia, it occurred a third time four months after ablation. This case shows that cardiac involvement in DMD may manifest also as WPW-syndrome. In these patients, repeated radio-frequency catheter ablation of accessory pathways may be necessary to completely block the re-entry mechanism. PMID:23508228

  5. Transcatheter radiofrequency ablation of atrial tissue using a suction catheter.

    PubMed

    Lavergne, T; Prunier, L; Cuize, L; Bruneval, P; Von Euw, D; Le Heuzey, J Y; Peronneau, P

    1989-01-01

    Closed chest ablative technique that avoid barotrauma would be attractive for ablation at thin walled cardiac structures, such as the atrial free wall or coronary sinus. Transcatheter radiofrequency (RF) currents produce tissue necrosis the size of which is dependent on the contact between the tissue and the electrode. In order to assess the effects of transvenous RF ablation of atrial free wall using a suction electrode catheter, we delivered in ten dogs, one single unmodulated RF pulse 1.2 MHz, in a unipolar mode, through the distal electrode of a lumen catheter (USCI 8F) (USCI, Billerica, MA USA) located in the right appendage. During the pulse an 80 KPa vacuum depression was applied to the lumen of the catheter. Each pulse had a 10 seconds duration and the mean delivered power was 4.3 +/- 1.4 W. Aortic pressure and electrocardiogram were monitored during the procedure. A right atrial electrophysiological study was performed at the ablated site, at control, after suction application and after RF pulse delivery. The animals were sacrificed after 14 or 21 days. Atrial pacing threshold values decreased after suction application in comparison to control values after the pulse (0.42 +/- 0.06 vs 0.60 +/- 0.23 mA, P less than O.05) but increased after the pulse delivery (2.60 +/- 1.85 mA, P less than 0.01). In contrast, the atrial effective refractory period did not significantly change after suction, nor after RF pulse delivery. Aortic pressure remained unchanged throughout the procedure. Complex arrhythmias were not observed during or after RF pulse delivery. One dog died suddenly at the first day after ablation, but this death was most probably unrelated to RF ablation. Anatomic lesions had a length of 8.8 +/- 3.3 mm, a width of 4.6 +/- 2.5 mm and a depth of 3.6 +/- 1.1 mm. They were transmural in nine of the ten dogs but without atrial wall perforation in any case. Lesions suggesting tissue volatilization were present in four dogs. These results demonstrate that

  6. 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.

  7. 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

  8. Radiofrequency catheter septal ablation for hypertrophic obstructive cardiomyopathy in children

    PubMed Central

    Emmel, M.; Sreeram, N.

    2005-01-01

    Background The definitive therapeutic options for symptomatic obstructive cardiomyopathy in childhood are restricted. At present, extensive surgical myectomy is the only procedure that is of proven benefit. Patients and Methods Three patients, aged 5, 11 and 17 years, respectively, with progressive hypertrophic obstructive cardiomyopathy and increasing symptoms were considered for radiofrequency catheter septal ablation. The peak Doppler gradient recorded on several occasions ranged between 50 to 90mmHg. Via a femoral arterial approach, the His bundle was initially plotted and marked using the LocaLisa navigation system. Subsequently, using a cooled tip catheter a series of lesions were placed in the hypertrophied septum, taking care to stay away from the His bundle. A total of 17, 50 and 45 lesions were applied in the three patients. In one case, the procedure was complicated by two episodes of ventricular fibrillation requiring DC cardioversion but without any neurological sequelae. Results The preablation peak-to-peak gradient between left ventricle and aorta was 50 mmHg, 60 mmHg and 60 mmHg, respectively, and remained unchanged immediately after the procedure. All patients were discharged from hospital 48 hours later. Serial measurement of serum troponin T and CK-MB isoenzyme confirmed significant myocardial necrosis. Follow-up echocardiography both at seven days and at six weeks postablation confirmed a beneficial haemodynamic result, with reduction of left ventricular outflow obstruction and relief of symptoms. Conclusion In young children, in whom alcohol-induced septal ablation is not an option, radiofrequency catheter ablation offers an alternative to surgery, with the benefits of repeatability and a lower risk of procedure-related permanent AV block. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:25696442

  9. [Catheter ablation of persistent atrial fibrillation : pulmonary vein isolation, ablation of fractionated electrograms, stepwise approach or rotor ablation?].

    PubMed

    Scherr, D

    2015-02-01

    Catheter ablation is an established treatment option for patients with atrial fibrillation (AF). In paroxysmal AF ablation, pulmonary vein isolation alone is a well-defined procedural endpoint, leading to success rates of up to 80% with multiple procedures over 5 years of follow-up. The success rate in persistent AF ablation is significantly more limited. This is partly due to the rudimentary understanding of the substrate maintaining persistent AF. Three main pathophysiological concepts for this arrhythmia exist: the multiple wavelet hypothesis, the concept of focal triggers, mainly located in the pulmonary veins and the rotor hypothesis. However, the targets and endpoints of persistent AF ablation are ill-defined and there is no consensus on the optimal ablation strategy in these patients. Based on these concepts, several ablation approaches for persistent AF have emerged: pulmonary vein isolation, the stepwise approach (i.e. pulmonary vein isolation, ablation of fractionated electrograms and linear ablation), magnetic resonance imaging (MRI) and rotor-based approaches. Currently, persistent AF ablation is a second-line therapy option to restore and maintain sinus rhythm. Several factors, such as the presence of structural heart disease, duration of persistent AF and dilatation and possibly also the degree of fibrosis of the left atrium should influence the decision to perform persistent AF ablation. PMID:25687615

  10. Cardiac tissue ablation with catheter-based microwave heating.

    PubMed

    Rappaport, C

    2004-11-01

    The common condition of atrial fibrillation is often treated by cutting diseased cardiac tissue to disrupt abnormal electrical conduction pathways. Heating abnormal tissue with electromagnetic power provides a minimally invasive surgical alternative to treat these cardiac arrhythmias. Radio frequency ablation has become the method of choice of many physicians. Recently, microwave power has also been shown to have great therapeutic benefit in medical treatment requiring precise heating of biological tissue. Since microwave power tends to be deposited throughout the volume of biological media, microwave heating offers advantages over other heating modalities that tend to heat primarily the contacting surface. It is also possible to heat a deeper volume of tissue with more precise control using microwaves than with purely thermal conduction or RF electrode heating. Microwave Cardiac Ablation (MCA) is used to treat heart tissue that allows abnormal electrical conduction by heating it to the point of inactivation. Microwave antennas that fit within catheter systems can be positioned close to diseased tissue. Specialized antenna designs that unfurl from the catheter within the heart can then radiate specifically shaped fields, which overcome problems such as excessive surface heating at the contact point. The state of the art in MCA is reviewed in this paper and a novel catheter-based unfurling wide aperture antenna is described. This antenna consists of the centre conductor of a coaxial line, shaped into a spiral and insulated from blood and tissue by a non-conductive fluid filled balloon. Initially stretched straight inside a catheter for transluminal guiding, once in place at the cardiac target, the coiled spiral antenna is advanced into the inflated balloon. Power is applied in the range of 50-150 W at the reserved industrial, scientific and medical (ISM) frequency of 915 MHz for 30-90 s to create an irreversible lesion. The antenna is then retracted back into the

  11. Influence of catheter orientation on lesion formation in bovine myocardium by using an open-irrigated laser ablation catheter.

    PubMed

    Sagerer-Gerhardt, Michaela; Weber, Helmut P

    2016-09-01

    Lesion sizes and quality are crucial for successful catheter ablation procedures. We sought to test the influence of catheter orientation towards the endocardial surface on lesion formation in bovine myocardium by using an open-irrigated laser ablation catheter. Continuous wave 1064-nm laser catheter applications at 15 W (4.5 W/mm²)/30 s, (135 J/mm²), irrigation flow 30 mL/min, were aimed at the left ventricular endocardial surface of bovine myocardium. The catheter was kept in vertical, in slanting (67.5°, 45°, 22.5°), and in flat positions; in flat position, also 60 s of radiation times were applied (n = 10, each). Lesions were evaluated morphometrically. Maximum depth of lesion was achieved with the catheter in a vertical orientation. Catheter inclination of <22.5 showed a highly significant decrease of lesion depth from 5.6 ± 1.1 to 3.7 ± 0.5 mm (p = 0.0001). In a flat catheter position, laser radiation of 30 s achieved the smallest lesions. However, after 60 s of radiation, the flat lesions were similar in depth (p = 087) and were larger in width (p = 0.0004) and in volumes (p = 0.0025) as compared to the lesions achieved with the catheter in vertical position after 30 s of radiation. Steam-pop with intramural cavitation or tissue vaporization with crater formation did not occur. Longer radiation times can achieve larger lesions regardless of catheter orientation. Catheter orientation is not a major determinant for laser ablation lesion size and quality, and a steerable support may not be needed when using the open-irrigated electrode-laser mapping and ablation (ELMA) catheter RytmoLas. PMID:27286865

  12. Reversal of ventricular premature beat induced cardiomyopathy by radiofrequency catheter ablation.

    PubMed

    Blaauw, Y; Pison, L; van Opstal, J M; Dennert, R M; Heesen, W F; Crijns, H J G M

    2010-10-01

    Frequent monomorphic ventricular premature beats (VPBs) may lead to left ventricular dysfunction. We describe two patients with frequent monomorphic VPBs and dilated cardiomyopathy in whom left ventricular function normalised after elimination of the VPBs by radiofrequency catheter ablation. The recent literature on this topic is summarised and potential candidates for catheter ablation are discussed. (Neth Heart J 2010;18:493-8.).

  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. Cost analysis of periprocedural imaging in patients undergoing catheter ablation for atrial fibrillation.

    PubMed

    Pokorney, Sean D; Hammill, Bradley G; Qualls, Laura G; Steinberg, Benjamin A; Curtis, Lesley H; Piccini, Jonathan P

    2014-07-15

    Cardiovascular imaging is an important part of procedural planning and safety for catheter ablation of atrial fibrillation (AF). However, the costs of imaging surrounding catheter ablation of AF have not been described. Medicare fee-for-service data were used to evaluate Medicare expenditures before, during, and after catheter ablation for AF from July 2007 to December 2009. Among 11,525 patients who underwent catheter ablation for AF, the mean overall expenditure on the day of the procedure was $14,455 (SD $7,441). The mean imaging expenditure in the periprocedural period, which included the 30 days before the catheter ablation and the day of the ablation itself, was $884 (SD $455). Periprocedural imaging expenditures varied by the imaging strategy used, ranging from a mean of $557 (SD $269) for patients with electroanatomic mapping only to $1,234 (SD $461) for patients with electroanatomic mapping, transesophageal echocardiogram, and computed tomography or magnetic resonance imaging. Mean patient-level imaging expenditures varied by provider (mean $872, SD $249). Periprocedural imaging expenditures also varied by patient risk, with mean expenditures of $862 (SD $444) for patients with a CHADS2 score of ≥2 compared with $907 (SD $466) for CHADS2 score<2 (p<0.001). In conclusion, periprocedural imaging accounts for approximately 6% of mean Medicare expenditures for catheter ablation of AF. The expenditures for periprocedural imaging vary both at the patient and at the provider level and they are inversely related to stroke risk by CHADS2 score. PMID:24952929

  15. [Discussion on the electromagnetic compatibility testing and evaluation of radio frequency ablation catheter].

    PubMed

    Wang, Yuji; Yang, Jiangang

    2014-11-01

    With the enforcement of YY 0505-2012, the testing items and evaluation points of radio frequency ablation catheter in electromagnetic compatibility field should be studied and discussed. Based on the requirements of relevant standards, this paper discusses on the testing items that should be applied and the evaluation points that should be focused on by analyzing the intended use and the structure of radio frequency ablation catheter, when it intends to apply registration individually with the basic knowledge of electromagnetic compatibility field.

  16. 3D ablation catheter localisation using individual C-arm x-ray projections

    NASA Astrophysics Data System (ADS)

    Haase, C.; Schäfer, D.; Dössel, O.; Grass, M.

    2014-11-01

    Cardiac ablation procedures during electrophysiology interventions are performed under x-ray guidance with a C-arm imaging system. Some procedures require catheter navigation in complex anatomies like the left atrium. Navigation aids like 3D road maps and external tracking systems may be used to facilitate catheter navigation. As an alternative to external tracking a fully automatic method is presented here that enables the calculation of the 3D location of the ablation catheter from individual 2D x-ray projections. The method registers a high resolution, deformable 3D attenuation model of the catheter to a 2D x-ray projection. The 3D localization is based on the divergent beam projection of the catheter. On an individual projection, the catheter tip is detected in 2D by image filtering and a template matching method. The deformable 3D catheter model is adapted using the projection geometry provided by the C-arm system and 2D similarity measures for an accurate 2D/3D registration. Prior to the tracking and registration procedure, the deformable 3D attenuation model is automatically extracted from a separate 3D cone beam CT reconstruction of the device. The method can hence be applied to various cardiac ablation catheters. In a simulation study of a virtual ablation procedure with realistic background, noise, scatter and motion blur an average 3D registration accuracy of 3.8 mm is reached for the catheter tip. In this study four different types of ablation catheters were used. Experiments using measured C-arm fluoroscopy projections of a catheter in a RSD phantom deliver an average 3D accuracy of 4.5 mm.

  17. 3D ablation catheter localisation using individual C-arm x-ray projections.

    PubMed

    Haase, C; Schäfer, D; Dössel, O; Grass, M

    2014-11-21

    Cardiac ablation procedures during electrophysiology interventions are performed under x-ray guidance with a C-arm imaging system. Some procedures require catheter navigation in complex anatomies like the left atrium. Navigation aids like 3D road maps and external tracking systems may be used to facilitate catheter navigation. As an alternative to external tracking a fully automatic method is presented here that enables the calculation of the 3D location of the ablation catheter from individual 2D x-ray projections. The method registers a high resolution, deformable 3D attenuation model of the catheter to a 2D x-ray projection. The 3D localization is based on the divergent beam projection of the catheter. On an individual projection, the catheter tip is detected in 2D by image filtering and a template matching method. The deformable 3D catheter model is adapted using the projection geometry provided by the C-arm system and 2D similarity measures for an accurate 2D/3D registration. Prior to the tracking and registration procedure, the deformable 3D attenuation model is automatically extracted from a separate 3D cone beam CT reconstruction of the device. The method can hence be applied to various cardiac ablation catheters. In a simulation study of a virtual ablation procedure with realistic background, noise, scatter and motion blur an average 3D registration accuracy of 3.8 mm is reached for the catheter tip. In this study four different types of ablation catheters were used. Experiments using measured C-arm fluoroscopy projections of a catheter in a RSD phantom deliver an average 3D accuracy of 4.5 mm.

  18. A novel four-wire-driven robotic catheter for radio-frequency ablation treatment

    PubMed Central

    Kato, Takahisa; Song, Sang-Eun; Hata, Nobuhiko

    2014-01-01

    Purpose Robotic catheters have been proposed to increase the efficacy and safety of the radio-frequency ablation treatment. The robotized motion of current robotic catheters mimics the motion of manual ones—namely, deflection in one direction and rotation around the catheter. With the expectation that the higher dexterity may achieve further efficacy and safety of the robotically driven treatment, we prototyped a four-wire-driven robotic catheter with the ability to deflect in two- degree-of-freedom motions in addition to rotation. Methods A novel quad-directional structure with two wires was designed and developed to attain yaw and pitch motion in the robotic catheter. We performed a mechanical evaluation of the bendability and maneuverability of the robotic catheter and compared it with current manual catheters. Results We found that the four-wire-driven robotic catheter can achieve a pitching angle of 184.7° at a pulling distance of wire for 11mm, while the yawing angle was 170.4° at 11mm. The robotic catheter could attain the simultaneous two- degree-of-freedom motions in a simulated cardiac chamber. Conclusion The results indicate that the four-wire-driven robotic catheter may offer physicians the opportunity to intuitively control a catheter and smoothly approach the focus position that they aim to ablate. PMID:24510205

  19. Evaluation of catheter ablation of periatrial ganglionic plexi in patients with atrial fibrillation.

    PubMed

    Danik, Stephan; Neuzil, Petr; d'Avila, Andre; Malchano, Zachary J; Kralovec, Stepan; Ruskin, Jeremy N; Reddy, Vivek Y

    2008-09-01

    Recent data suggests that the cardiac autonomic nervous system has an important role in the initiation and maintenance of atrial fibrillation (AF). This study investigated (1) the feasibility of identifying and targeting these autonomic ganglia using endocardial radiofrequency stimulation and ablation, respectively; (2) the efficacy of endocardial ablation to completely eliminate the vagal response elicited from epicardial stimulation; and (3) the effect of autonomic ablation on the acute inducibility of AF. The study included 18 patients referred for catheter ablation of suspected vagal-mediated AF. The endocardial left atrial surface was stimulated at high frequency (20 to 50 Hz) to elicit a vagal response. In selected patients (n = 5), pericardial access was obtained using a subxyphoid puncture to permit epicardial stimulation. Catheter ablation of the putative autonomic ganglionic sites was performed from the left atrial endocardium using irrigated radiofrequency energy. After ablation of all identifiable autonomic ganglia, high-frequency pacing was repeated to induce AF. In all patients, stimulation at certain endocardial sites elicited a vagal response. Endocardial ablation abrogated this vagal responsiveness. Furthermore, for sites accessible from the pericardium, the vagal response elicited using epicardial stimulation was also eliminated. Despite successful ablation of these ganglia, AF was still inducible in 17 of 18 patients. In conclusion, successful ablation of autonomic ganglia from an endocardial approach can be reliably achieved using an irrigated catheter. In addition, ablation of these structures in patients with vagal-mediated AF is insufficient to prevent its acute reinduction with high-frequency atrial stimulation. PMID:18721515

  20. [Catheter ablation of focus triggering ventricular fibrillation in patients with structural heart disease].

    PubMed

    Kautzner, Josef; Peichl, Petr

    2014-12-01

    First experiences with ablation of focus triggering ventricular fibrillation were reported in isolated cases of idiopathic ventricular fibrillation. Later, there were described the options in management of an electrical instability triggered by ectopic activity in patients after myocardial infarction. In both cases it was shown that the sources of extrasystoles originate almost exclusively from conducting system of chambers. Subsequently, isolated cases were also reported in other structural diseases. It is important that the urgent catheter ablation is able to remove focus which triggers electric instability. In many cases it is a lifesaving procedure. This review summarizes the current knowledge of the catheter ablation of focus triggering ventricular fibrillation with structural heart disease.

  1. 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

  2. Remote Magnetic Navigation: A Focus on Catheter Ablation of Ventricular Arrhythmias.

    PubMed

    Aagaard, Philip; Natale, Andrea; Briceno, David; Nakagawa, Hiroshi; Mohanty, Sanghamitra; Gianni, Carola; Burkhardt, J David; DI Biase, Luigi

    2016-03-01

    VT ablation is based on percutaneous catheter insertion under fluoroscopic guidance to selectively destroy (i.e., ablate) myocardial tissue regions responsible for the initiation or propagation of ventricular arrhythmias. Although the last decade has witnessed a rapid evolution of ablation equipment and techniques, the control over catheter movement during manual ablation has remained largely unchanged. Moreover, the procedures are long, and require ergonomically unfavorable positions, which can lead to operator fatigue. In an attempt to overcome these constraints, several technical advancements, including remote magnetic navigation (RMN), have been developed. RMN utilizes a magnetic field to remotely manipulate specially designed soft-tip ablation catheters anywhere in the x, y, or z plane inside the patient's chest. RMN also facilitates titration of the contact force between the catheter and the myocardial tissue, which may reduce the risk of complications while ensuring adequate lesion formation. There are several non-randomized studies showing that RMN has similar efficacy to manual ablation, while complication rates and total radiation exposure appears to be lower. Although these data are promising, larger randomized studies are needed to prove that RMN is superior to manual ablation of VT.

  3. A method for guiding ablation catheters to arrhythmogenic sites using body surface electrocardiographic signals.

    PubMed

    Barley, Maya E; Armoundas, Antonis A; Cohen, Richard J

    2009-03-01

    Treatment of hemodynamically unstable ventricular arrhythmias requires rapid and accurate localization of the reentrant circuit. We have previously described an algorithm that uses the single-equivalent moving dipole model to rapidly identify both the location of cardiac sources from body surface electrocardiographic signals and the location of the ablation catheter tip from current pulses delivered at the tip. However, during catheter ablation, in the presence of sources of systematic error, even if the exit site and catheter tip dipole are superposed in real space, their calculated positions may be separated by as much as 5 mm if their orientations are not exactly matched. In this study, we present a method to compensate for the effect of dipole orientation and examine the method's ability to guide a dipole at a catheter tip to an arrhythmogenic dipole corresponding to the exit site. In computer simulations, we show that the new method enables the user to guide the catheter tip to within 1.5 mm of the arrhythmogenic dipole using a realistic number of movements of the ablation catheter. These results suggest that this method has the potential to greatly facilitate RF ablation procedures, especially in the significant patient population with hemodynamically unstable arrhythmias. PMID:19272900

  4. Cost Analysis of Periprocedural Imaging in Patients Undergoing Catheter Ablation for Atrial Fibrillation

    PubMed Central

    Pokorney, Sean D.; Hammill, Bradley G.; Qualls, Laura G.; Steinberg, Benjamin A.; Curtis, Lesley H.; Piccini, Jonathan P.

    2014-01-01

    Cardiovascular imaging is an important part of procedural planning and safety for catheter ablation of atrial fibrillation (AF). However, the costs of imaging surrounding catheter ablation of AF have not been described. Medicare fee-for-service data were used to evaluate Medicare expenditures before, during, and after catheter ablation for AF from July 2007 to December 2009. Among 11,525 patients who underwent catheter ablation for AF, the mean overall expenditure on the day of the procedure was $14,455 (SD $7,441). The mean imaging expenditure in the periprocedural period, which included the 30 days before the catheter ablation and the day of the ablation itself, was $884 (SD $455). Periprocedural imaging expenditures varied by the imaging strategy used, ranging from a mean of $557 (SD $269) for patients with electroanatomic mapping only to $1,234 (SD $461) for patients with electroanatomic mapping, transesophageal echocardiogram, and computed tomography or magnetic resonance imaging. Mean patient-level imaging expenditures varied by provider (mean $872, SD $249). Periprocedural imaging expenditures also varied by patient risk, with mean expenditures of $862 (SD $444) for patients with a CHADS2 score of ≥2 compared with $907 (SD $466) for CHADS2 score <2 (p <0.001). In conclusion, peri-procedural imaging accounts for approximately 6% of mean Medicare expenditures for catheter ablation of AF. The expenditures for periprocedural imaging vary both at the patient and at the provider level and they are inversely related to stroke risk by CHADS2 score. PMID:24952929

  5. Radiofrequency catheter ablation in pediatric patients with supraventricular arrhythmias.

    PubMed

    Rhodes, L A; Lobban, J H; Schmidt, S B

    1995-01-01

    Radiofrequency (RF) ablation of foci leading to abnormal cardiac rhythms is rapidly becoming the procedure of choice in the management of arrhythmias in adults. This report reviews our initial experience with RF ablation in the pediatric population. PMID:8533398

  6. Atrial fibrillation disorganization is reduced by catheter ablation: a standard ECG study.

    PubMed

    Bonizzi, Pietro; Meste, Olivier; Zarzoso, Vicente; Latcu, Decebal Gabriel; Popescu, Irina; Ricard, Philippe; Saoudi, Nadir

    2010-01-01

    Selection of candidates to catheter ablation (CA) of long-lasting persistent atrial fibrillation (AF) is challenging, since success is not guaranteed. In this study, we put forward an automated method for noninvasively evaluating the reduction of the complexity of the AF organization following CA. Complexity is meant as the amount of disorganization observed on the ECG, supposed to be directly correlated to the number and interactions of atrial wavefronts. By means of PCA, the complexity of the AF organization is evaluated quantitatively from a 12-lead ECG recording. Preliminary results show that CA is able to reduce the complexity of AF organization in the atrial wavefront pattern propagation, despite the persistence of AF in most cases. This can be viewed as a first clinical validation of this parameter. Whether AF complexity and its reduction by CA are predictive of long-term outcome is thus still to be determined.

  7. Gender, Race, and Health Insurance Status in Patients Undergoing Catheter Ablation for Atrial Fibrillation.

    PubMed

    Patel, Nileshkumar; Deshmukh, Abhishek; Thakkar, Badal; Coffey, James O; Agnihotri, Kanishk; Patel, Achint; Ainani, Nitesh; Nalluri, Nikhil; Patel, Nilay; Patel, Nish; Patel, Neil; Badheka, Apurva O; Kowalski, Marcin; Hendel, Robert; Viles-Gonzalez, Juan; Noseworthy, Peter A; Asirvatham, Samuel; Lo, Kaming; Myerburg, Robert J; Mitrani, Raul D

    2016-04-01

    Catheter ablation for atrial fibrillation (AF) has emerged as a popular procedure. The purpose of this study was to examine whether there exist differences or disparities in ablation utilization across gender, socioeconomic class, insurance, or race. Using the Nationwide Inpatient Sample (2000 to 2012), we identified adults hospitalized with a principal diagnosis of AF by ICD 9 code 427.31 who had catheter ablation (ICD 9 code-37.34). We stratified patients by race, insurance status, age, gender, and hospital characteristics. A hierarchical multivariate mixed-effect model was created to identify the independent predictors of AF ablation. Among an estimated total of 3,508,122 patients (extrapolated from 20% Nationwide Inpatient Sample) hospitalized with a diagnosis of AF in the United States from the year 2000 to 2012, 102,469 patients (2.9%) underwent catheter ablations. The number of ablations was increased by 940%, from 1,439 in 2000 to 15,090 in 2012. There were significant differences according to gender, race, and health insurance status, which persisted even after adjustment for other risk factors. Female gender (0.83 [95% CI 0.79 to 0.87; p <0.001]), black (0.49 [95% CI 0.44 to 0.55; p <0.001]), and Hispanic race (0.64 [95% CI 0.56 to 0.72; p <0.001]) were associated with lower likelihoods of undergoing an AF ablation. Medicare (0.93, 0.88 to 0.98, <0.001) or Medicaid (0.67, 0.59 to 0.76, <0.001) coverage and uninsured patients (0.55, 0.49 to 0.62, <0.001) also had lower rates of AF ablation compared to patients with private insurance. In conclusion we found differences in utilization of catheter ablation for AF based on gender, race, and insurance status that persisted over time. PMID:26899494

  8. Healthcare Utilization and Clinical Outcomes after Catheter Ablation of Atrial Flutter

    PubMed Central

    Dewland, Thomas A.; Glidden, David V.; Marcus, Gregory M.

    2014-01-01

    Atrial flutter ablation is associated with a high rate of acute procedural success and symptom improvement. The relationship between ablation and other clinical outcomes has been limited to small studies primarily conducted at academic centers. We sought to determine if catheter ablation of atrial flutter is associated with reductions in healthcare utilization, atrial fibrillation, or stroke in a large, real world population. California Healthcare Cost and Utilization Project databases were used to identify patients undergoing atrial flutter ablation between 2005 and 2009. The adjusted association between atrial flutter ablation and healthcare utilization, atrial fibrillation, or stroke was investigated using Cox proportional hazards models. Among 33,004 patients with a diagnosis of atrial flutter observed for a median of 2.1 years, 2,733 (8.2%) underwent catheter ablation. Atrial flutter ablation significantly lowered the adjusted risk of inpatient hospitalization (HR 0.88, 95% CI 0.84–0.92, p<0.001), emergency department visits (HR 0.60, 95% CI 0.54–0.65, p<0.001), and overall hospital-based healthcare utilization (HR 0.94, 95% CI 0.90–0.98, p = 0.001). Atrial flutter ablation was also associated with a statistically significant 11% reduction in the adjusted hazard of atrial fibrillation (HR 0.89, 95% CI 0.81–0.97, p = 0.01). Risk of acute stroke was not significantly reduced after ablation (HR 1.09, 95% CI 0.81–1.45, p = 0.57). In a large, real world population, atrial flutter ablation was associated with significant reductions in hospital-based healthcare utilization and a reduced risk of atrial fibrillation. These findings support the early use of catheter ablation for the treatment of atrial flutter. PMID:24983868

  9. Adjusted Left Atrial Emptying Fraction as a Predictor of Procedural Outcome after Catheter Ablation for Atrial Fibrillation

    PubMed Central

    Im, Sung Il; Kim, Sun Won; Choi, Cheol Ung; Kim, Jin Won; Yong, Hwan Seok; Kim, Eung Ju; Rha, Seung-Woon; Park, Chang Gyu; Seo, Hong Seog; Oh, Dong Joo; Lim, Hong Euy

    2015-01-01

    Structural remodeling of the left atrium is a risk factor for recurrent arrhythmia after catheter ablation for atrial fibrillation; however, data are sparse regarding the role of functional left atrial remodeling in predicting procedural outcomes. We evaluated whether left atrial transport function could be used to predict recurrent atrial fibrillation. From July 2008 through August 2010, we enrolled 202 consecutive patients who underwent catheter ablation for atrial fibrillation (paroxysmal=120, persistent=82). Left atrial volumes (LAVs) were measured by means of multislice computed tomography at every 10% of the R-R interval, and measurements were adjusted for body surface area to yield the LAV index (LAVI) at baseline. The left atrial emptying fraction (LAEF) was calculated according to LAV differences. During the mean follow-up period of 10 ± 4 months after a single ablation procedure, atrial fibrillation recurred in 59 patients (paroxysmal=19, persistent=40). Multivariate analysis revealed that persistent atrial fibrillation, early mitral inflow velocity, LAVImax, LAVImin, LAEF, LAVImax/LAEF, and LAVImin/LAEF were all independent predictors of atrial fibrillation, but the best predictor was LAVImin/LAEF (β=1.329, P=0.001). The cutoff value was 1.61 (mL/m2)/%, and the sensitivity and specificity were 74.6% and 62.2%, respectively (area under the curve=0.761). Our study shows that adjusted left atrial emptying fraction with use of multislice computed tomography might be a useful, noninvasive method to select patients for ablation. PMID:26175632

  10. Successful control of life-threatening polymorphic ventricular tachycardia by radiofrequency catheter ablation in an infant.

    PubMed

    Abe, Yuriko; Sumitomo, Naokata; Okuma, Hiromi; Nakamura, Takahiro; Fukuhara, Junji; Ichikawa, Rie; Matsumura, Masaharu; Miyashita, Michio; Kamiyama, Hiroshi; Ayusawa, Mamoru; Watanabe, Mamie; Joo, Kunitaka; Makita, Naomasa; Horie, Minoru

    2014-05-01

    We present a case of a 9-month-old girl in whom malignant polymorphic ventricular tachycardia (VT) was successfully controlled by radiofrequency catheter ablation under guidance with a three-dimensional mapping system. The VTs originated from the left ventricular lateral wall, left ventricular anterior wall, and left ventricular apex. At least six types of VTs were documented during the electrophysiology study. All VTs were successfully controlled after two sessions of radiofrequency catheter ablation, and she was discharged from our hospital on propranolol, mexiletine, flecainide, and aprindine. PMID:23836069

  11. 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.

  12. Local Electrical Dyssynchrony during Atrial Fibrillation: Theoretical Considerations and Initial Catheter Ablation Results

    PubMed Central

    Schäffer, Benjamin; Hoffmann, Boris A.; Ganesan, Anand N.; Schreiber, Doreen; Moser, Julia M.; Akbulak, Ruken Ö.; Sultan, Arian; Steven, Daniel; Maesen, Bart; Schotten, Ulrich; Meyer, Christian; Willems, Stephan

    2016-01-01

    Background Electrogram-based identification of the regions maintaining persistent Atrial Fibrillation (AF) is a subject of ongoing debate. Here, we explore the concept of local electrical dyssynchrony to identify AF drivers. Methods and Results Local electrical dyssynchrony was calculated using mean phase coherence. High-density epicardial mapping along with mathematical model were used to explore the link between local dyssynchrony and properties of wave conduction. High-density mapping showed a positive correlation between the dyssynchrony and number of fibrillatory waves (R2 = 0.68, p<0.001). In the mathematical model, virtual ablation at high dyssynchrony regions resulted in conduction regularization. The clinical study consisted of eighteen patients undergoing catheter ablation of persistent AF. High-density maps of left atrial (LA) were constructed using a circular mapping catheter. After pulmonary vein isolation, regions with the top 10% of the highest dyssynchrony in LA were targeted during ablation and followed with ablation of complex atrial electrograms. Catheter ablation resulted in termination during ablation at high dyssynchrony regions in 7 (41%) patients. In another 4 (24%) patients, transient organization was observed. In 6 (35%) there was no clear effect. Long-term follow-up showed 65% AF freedom at 1 year and 22% at 2 years. Conclusions Local electrical dyssynchrony provides a reasonable estimator of regional AF complexity defined as the number of fibrillatory waves. Additionally, it points to regions of dynamical instability related with action potential alternans. However, despite those characteristics, its utility in guiding catheter ablation of AF is limited suggesting other factors are responsible for AF persistence. PMID:27780243

  13. Demographic Differences in Catheter Ablation After Hospital Presentation With Symptomatic Atrial Fibrillation

    PubMed Central

    Kummer, Benjamin R; Bhave, Prashant D; Merkler, Alexander E; Gialdini, Gino; Okin, Peter M; Kamel, Hooman

    2015-01-01

    Background Catheter ablation is increasingly used for rhythm control in symptomatic atrial fibrillation (AF), but the demographic characteristics of patients undergoing this procedure are unclear. Methods and Results We used data on all admissions at nonfederal acute care hospitals in California, Florida, and New York to identify patients discharged with a primary diagnosis of AF between 2006 and 2011. Our primary outcome was readmission for catheter ablation of AF, identified using validated International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes. Cox regression models were used to assess relationships between demographic characteristics and catheter ablation, adjusting for Elixhauser comorbidities. We identified 397 612 eligible patients. Of these, 16 717 (4.20%, 95% CI 0.41 to 0.43) underwent ablation. These patients were significantly younger, more often male, more often white, and more often privately insured, with higher household incomes and lower rates of medical comorbidity. In Cox regression models, the likelihood of ablation was lower in women than men (hazard ratio [HR] 0.83; 95% CI 0.80 to 0.86) despite higher rates of AF-related rehospitalization (HR 1.23; 95% CI 1.21 to 1.24). Compared to whites, the likelihood of ablation was lower in Hispanics (HR 0.60; 95% CI 0.56 to 0.64) and blacks (HR 0.68; 95% CI 0.64 to 0.73), even though blacks had only a slightly lower likelihood of AF-related rehospitalization (HR 0.97; 95% CI 0.94 to 0.99) and a higher likelihood of all-cause hospitalization (HR 1.38; 95% CI 1.37 to 1.39). Essentially the same pattern existed in Hispanics. Conclusions We found differences in use of catheter ablation for symptomatic AF according to sex and race despite adjustment for available data on demographic characteristics and medical comorbidities. PMID:26396201

  14. Reversal of premature ventricular complex-induced cardiomyopathy following successful radiofrequency catheter ablation.

    PubMed

    Efremidis, Michalis; Letsas, Konstantinos P; Sideris, Antonios; Kardaras, Fotios

    2008-06-01

    Premature ventricular complex (PVC)-induced cardiomyopathy is an underappreciated cause of left-ventricular (LV) dysfunction. The present report describes the case of an elderly man with a very high burden of monomorphic PVCs and LV dysfunction. Elimination of the left ventricular focus following radiofrequency catheter ablation resulted in reversal of cardiomyopathy.

  15. Predictors of atrial fibrillation termination and clinical success of catheter ablation of persistent atrial fibrillation.

    PubMed

    Heist, E Kevin; Chalhoub, Fadi; Barrett, Conor; Danik, Stephan; Ruskin, Jeremy N; Mansour, Moussa

    2012-08-15

    The termination of persistent atrial fibrillation (AF) during catheter ablation has been associated in some, but not all, studies with reduced arrhythmia during clinical follow-up. We sought to determine the rate of persistent AF termination achievable with a stepwise ablation strategy, the predictors of AF termination, and the clinical outcomes associated with termination and nontermination. A total of 143 consecutive patients (age 62 ± 9 years, AF duration 5.7 ± 5.2 years) with persistent and longstanding persistent AF resistant to antiarrhythmic medication who presented in AF for catheter ablation were studied. Ablation was done with a stepwise approach, including pulmonary vein isolation, followed by complex fractionated atrial electrogram ablation and ablation of resultant atrial tachycardias. Clinical follow-up was then performed after a 2-month blanking period to assess arrhythmia recurrence, defined as AF or atrial tachycardia lasting ≥ 30 seconds. AF termination by ablation was achieved in 95 (66%) of the 143 patients. Multivariate predictors of AF termination included longer baseline AF cycle length (p <0.001) and smaller left atrial size (p = 0.002). AF termination by ablation was associated with both a lower incidence of arrhythmia recurrence after a single procedure without antiarrhythmic drugs (p = 0.01) and overall clinical success (single or multiple procedures, with or without antiarrhythmic drugs; p = 0.005). On multivariate analysis, the predictors of overall clinical success included AF termination by ablation (p = 0.001), a shorter ablation duration (p = 0.002), younger age (p = 0.02), male gender (p = 0.03), and the presence of hypertension (p = 0.03). In conclusion, among patients with persistent AF, termination of AF by ablation can be achieved in most patients and is associated with reduced recurrence of arrhythmia. PMID:22591670

  16. Impact of computed tomography image and contact force technology on catheter ablation for atrial fibrillation

    PubMed Central

    Marai, Ibrahim; Suleiman, Mahmoud; Blich, Miry; Lessick, Jonathan; Abadi, Sobhi; Boulos, Monther

    2016-01-01

    AIM: To investigate the impact of using computed tomography (CT) and contact force (CF) technology on recurrence of atrial tachyarrhythmia after atrial fibrillation (AF) ablation. METHODS: This non-randomized study included 2 groups of patients. All patients had symptomatic recurrent paroxysmal or persistent AF and were treated with at least 1 anti arrhythmic medication or intolerant to medication. The first group included 33 patients who underwent circumferential pulmonary veins isolation (PVI) for AF during 2012 and 2013 guided by CT image integration (Cartomerge, Biosense Webster, Diamond Bar, CA, United States) of left atrium and pulmonary veins into an electroanatomic mapping (EAM) system (CT group) using standard irrigated radiofrequency catheter (ThermoCool, Carto, Biosense Webster, Diamond Bar, CA, United States) or irrigated catheter with integrated CF sensor (Smart Touch, Carto, Biosense Webster, Diamond Bar, CA, United States). The second group included immediately preceding 32 patients who had circumferential PVI by standard irrigated catheter (ThermoCool) using only EAM (Carto) system (EAM group). Linear lesions were performed according to the discretion of operator. RESULTS: Sex, age, and persistent AF were not different between groups. PVI was achieved in all patients in both groups. Linear ablations including cavo-tricuspid isthmus and or roof line ablation were not different between groups. Free of atrial tachyarrhythmia during follow-up of 24 mo was significantly higher among CT group compared to EAM group (81% vs 55%; respectively; P = 0.027). When 11 patients from CT group who had ablation using Smart Touch catheter were excluded, the difference between CT group and EAM became non significant (73% vs 55%; respectively; P = 0.16). Sub analysis of CT group showed that patients who had ablation using Smart Touch catheter tend to be more free of atrial tachyarrhythmia compared to patients who had ablation using standard irrigated catheter during

  17. [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. PMID:11481116

  18. Radiofrequency ablation with a vibrating catheter: A new method for electrode cooling.

    PubMed

    Yu, Kaihong; Yamashita, Tetsui; Shingyochi, Shigeaki; Matsumoto, Kazuo; Ohta, Makoto

    2016-05-01

    A new electrode cooling system using a vibrating catheter is described for conditions of low blood flow when saline irrigation cannot be used. Vibrations of the catheter are hypothesized to disturb blood flow around the electrode, leading to increased convective cooling of the electrode. The aim of this study is to confirm the cooling effect of vibration and investigate the associated mechanisms. As methods, an in vitro system with polyvinyl alcohol-hydrogel (PVA-H) as ablated tissue and saline flow in an open channel was used to measure changes in electrode and tissue temperatures under vibration of 0-63 Hz and flow velocity of 0-0.1 m/s. Flow around the catheter was observed using particle image velocimetry (PIV). Results show that under conditions of no flow, electrode temperatures decreased with increasing vibration frequency, and in the absence of vibrations, electrode temperatures decreased with increasing flow velocity. In the presence of vibrations, electrode temperatures decreased under conditions of low flow velocity, but not under those of high flow velocity. PIV analyses showed disturbed flow around the vibrating catheter, and flow velocity around the catheter increased with higher-frequency vibrations. In conclusion, catheter vibration facilitated electrode cooling by increasing flow around the catheter, and cooling was proportional to vibration frequency.

  19. Catheter ablation for ventricular tachyarrhythmias in patients supported by continuous-flow left ventricular assist devices.

    PubMed

    Garan, Arthur R; Iyer, Vivek; Whang, William; Mody, Kanika P; Yuzefpolskaya, Melana; Colombo, Paolo C; Te-Frey, Rosie; Takayama, Hiroo; Naka, Yoshifumi; Garan, Hasan; Jorde, Ulrich P; Uriel, Nir

    2014-01-01

    Ventricular arrhythmias (VAs) are common after implantation of a left ventricular assist device (LVAD) and in a subset of patients may be refractory to medication. Morbidity from VA in this population includes right ventricular failure (RVF). We sought to evaluate the efficacy of catheter ablation for VA in patients with LVAD. A retrospective analysis of patients supported by continuous-flow LVAD referred for catheter ablation of ventricular tachycardia (VT) between 2008 and the present was performed. Seven patients were referred for VT ablation an average of 236 ± 292 days after LVAD implantation. Three patients (42.9%) developed RVF in the setting of intractable arrhythmias. A transfemoral approach was used for six patients (85.7%) and an epicardial for one patient (14.3%). The clinical VT was inducible and successfully ablated in six patients (85.7%). The location of these arrhythmias was apical in three cases (42.9%). A total of 13 VTs were ablated in seven patients. Although the majority had reduction in VA frequency, recurrent VAs were observed in six patients (85.7%). One patient (14.3%) experienced a bleeding complication after the procedure. For patients with a high VA burden after LVAD implantation, VT ablation is safe and feasible, but VA frequently recurs.

  20. Capturing Pain in the Cortex during General Anesthesia: Near Infrared Spectroscopy Measures in Patients Undergoing Catheter Ablation of Arrhythmias

    PubMed Central

    Yücel, Meryem A.; Steele, Sarah C.; Alexander, Mark E.; Boas, David A.; Borsook, David; Becerra, Lino

    2016-01-01

    The predictability of pain makes surgery an ideal model for the study of pain and the development of strategies for analgesia and reduction of perioperative pain. As functional near-infrared spectroscopy reproduces the known functional magnetic resonance imaging activations in response to a painful stimulus, we evaluated the feasibility of functional near-infrared spectroscopy to measure cortical responses to noxious stimulation during general anesthesia. A multichannel continuous wave near-infrared imager was used to measure somatosensory and frontal cortical activation in patients undergoing catheter ablation of arrhythmias under general anesthesia. Anesthetic technique was standardized and intraoperative NIRS signals recorded continuously with markers placed in the data set for the timing and duration of each cardiac ablation event. Frontal cortical signals only were suitable for analysis in five of eight patients studied (mean age 14 ± 1 years, weight 66.7 ± 17.6 kg, 2 males). Thirty ablative lesions were recorded for the five patients. Radiofrequency or cryoablation was temporally associated with a hemodynamic response function in the frontal cortex characterized by a significant decrease in oxyhemoglobin concentration (paired t-test, p<0.05) with the nadir occurring in the period 4 to 6 seconds after application of the ablative lesion. Cortical signals produced by catheter ablation of arrhythmias in patients under general anesthesia mirrored those seen with noxious stimulation in awake, healthy volunteers, during sedation for colonoscopy, and functional Magnetic Resonance Imaging activations in response to pain. This study demonstrates the feasibility and potential utility of functional near-infrared spectroscopy as an objective measure of cortical activation under general anesthesia. PMID:27415436

  1. 3D X-ray imaging methods in support catheter ablations of cardiac arrhythmias.

    PubMed

    Stárek, Zdeněk; Lehar, František; Jež, Jiří; Wolf, Jiří; Novák, Miroslav

    2014-10-01

    Cardiac arrhythmias are a very frequent illness. Pharmacotherapy is not very effective in persistent arrhythmias and brings along a number of risks. Catheter ablation has became an effective and curative treatment method over the past 20 years. To support complex arrhythmia ablations, the 3D X-ray cardiac cavities imaging is used, most frequently the 3D reconstruction of CT images. The 3D cardiac rotational angiography (3DRA) represents a modern method enabling to create CT like 3D images on a standard X-ray machine equipped with special software. Its advantage lies in the possibility to obtain images during the procedure, decreased radiation dose and reduction of amount of the contrast agent. The left atrium model is the one most frequently used for complex atrial arrhythmia ablations, particularly for atrial fibrillation. CT data allow for creation and segmentation of 3D models of all cardiac cavities. Recently, a research has been made proving the use of 3DRA to create 3D models of other cardiac (right ventricle, left ventricle, aorta) and non-cardiac structures (oesophagus). They can be used during catheter ablation of complex arrhythmias to improve orientation during the construction of 3D electroanatomic maps, directly fused with 3D electroanatomic systems and/or fused with fluoroscopy. An intensive development in the 3D model creation and use has taken place over the past years and they became routinely used during catheter ablations of arrhythmias, mainly atrial fibrillation ablation procedures. Further development may be anticipated in the future in both the creation and use of these models.

  2. Catheter Ablation of Arrhythmias Exclusively Using Electroanatomic Mapping: A Series of Cases

    PubMed Central

    Pires, Leonardo Martins; Leiria, Tiago Luiz Luz; Kruse, Marcelo Lapa; Ronsoni, Rafael; Gensas, Caroline Saltz; de Lima, Gustavo Glotz

    2013-01-01

    Background Catheter ablation is a treatment that can cure various cardiac arrhythmias. Fluoroscopy is used to locate and direct catheters to areas that cause arrhythmias. However, fluoroscopy has several risks. Electroanatomic mapping (EAM) facilitates three-dimensional imaging without X-rays, which reduces risks associated with fluoroscopy. Objective We describe a series of patient cases wherein cardiac arrhythmia ablation was exclusively performed using EAM. Methods Patients who presented with cardiac arrhythmias that were unresponsive to pharmacological therapy were prospectively selected between March 2011 and March 2012 for arrhythmia ablation exclusively through EAM. Patients with indications for a diagnostic electrophysiology study and ablation of atrial fibrillation, left atrial tachyarrhythmias as well as hemodynamically unstable ventricular arrhythmia were excluded. We documented the procedure time, success rate and complications as well as whether fluoroscopy was necessary during the procedure. Results In total, 11 patients were enrolled in the study, including seven female patients (63%). The mean age of the patients was 50 years (SD ±16.5). Indications for the investigated procedures included four cases (35%) of atrial flutter, three cases (27%) of pre-excitation syndrome, two cases (19%) of paroxysmal supraventricular tachycardia and two cases (19%) of ventricular extrasystoles. The mean procedure duration was 86.6 min (SD ± 26 min). Immediate success (at discharge) of the procedure was evident for nine patients (81%). There were no complications during the procedures. Conclusion This study demonstrates the feasibility of performing an arrhythmia ablation exclusively using EAM with satisfactory results. PMID:23877742

  3. Radiofrequency catheter ablation of Type 1 atrial flutter using a large-tip electrode catheter and high-power radiofrequency energy generator.

    PubMed

    Feld, Gregory K

    2004-11-01

    Recent studies have demonstrated a high degree of efficacy of 8 mm electrode-tipped or saline-irrigated-tip catheters for ablation of atrial flutter (AFL). These catheters have a theoretical advantage as they produce a large ablation lesion. However, large-tip ablation catheters have a larger surface area and require a higher power radiofrequency (RF) generator with up to 100 W capacity to produce adequate ablation temperatures (50-60 degrees C). The potential advantages of a large-tip ablation catheter and high-power RF generator include the need for fewer energy applications, shorter procedure and fluoroscopy times, and greater efficacy. Therefore, the safety and efficacy of AFL ablation using 8 or 10 mm electrode catheters and a 100-W RF generator was studied using the Boston Scientific, Inc., EPT-1000 XP cardiac ablation system. There were 169 patients, aged 61 +/- 12 years involved. Acute end points were bidirectional isthmus block and no inducible AFL. Following ablation, patients were seen at 1, 3 and 6 months, with event monitoring performed weekly and for any symptoms. Three quality of life surveys were completed during follow-up. Acute success was achieved in 158 patients (93%), with 12 +/- 11 RF energy applications. The efficacy of 8 and 10 mm electrodes did not differ significantly. The number of RF energy applications (10 +/- 8 vs. 14 +/- 8) and ablation time (0.5 +/- 0.4 vs. 0.8 +/- 0.6 h) were less with 10 mm compared with 8 mm electrodes (p < 0.01). Of 158 patients with acute success, 42 were not evaluated at 6 months due to study exclusions. Of the 116 patients evaluated at 6 months, 112 (97%) had no AFL recurrence. Of those without AFL recurrence at 6 months, 95 and 93% were free of symptoms at 12 and 24 months, respectively. Ablation of AFL improved quality of life scores (p < 0.05) and reduced anti-arrhythmic and rate control drug use (p < 0.05). Complications occurred in six out of 169 patients (3.6%) but there were no deaths. It was concluded

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

    PubMed

    Yamagata, Kenichiro; Aldhoon, Bashar; Kautzner, Josef

    2016-08-01

    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

  5. Successful non-operative management of left atrioesophageal fistula following catheter ablation.

    PubMed

    Shiraishi, Manabu; Morita, Hideki; Muramatsu, Kenichi; Sato, Akira; Nitta, Junichi; Yamaguchi, Atsushi; Adachi, Hideo

    2014-08-01

    Atrioesophageal fistula (AEF) is a potentially lethal complication of catheter radiofrequency ablation for atrial fibrillation. A 49-year-old man with paroxysmal atrial fibrillation who underwent catheter ablation around the pulmonary vein was admitted 31 days after the procedure, suffering seizures and fever. Magnetic resonance imaging of the brain showed ischemia and multiple lesions of acute infarction in the right occipital lobe of the cerebrum. Computed tomography (CT) of the chest showed a small accumulation of air between the posterior left atrium and the esophagus, suggesting an AEF. Endoscopic snaring of the esophageal mucosa, repeated a few times, supported by nil by mouth and antibiotic therapy, resulted in improvement of his condition with no recurrence of symptoms. Subsequent chest CT scans confirmed disappearance of the leaked air and the patient was discharged home 45 days after admission with no neurological compromise.

  6. Combined Therapeutic and Monitoring Ultrasonic Catheter for Cardiac Ablation Therapies.

    PubMed

    Carias, Mathew; Hynynen, Kullervo

    2016-01-01

    This study evaluated the feasibility of a combined therapeutic and diagnostic ultrasonic catheter for cardiac ablation therapies. Ultrasound can be used to determine when diseased cardiac tissues have become fully coagulated through a method known as local harmonic motion imaging (LHMI). LHMI is an imaging modality for treatment monitoring that uses acoustic radiation force, displacement tracking and the different mechanical properties of viable and ablated tissues. In this study, we developed catheters that are capable of LHMI measurements. Experiments were conducted in phantoms, ex vivo cardiac samples and the in vivo beating hearts of healthy porcine subjects. In vivo experiments revealed that four of four epicardial sonications revealed a decrease in measured displacements from LHMI experiments and that when lower power was used, no lesions formed and there was no corresponding decrease in measured displacement amplitudes. In addition, two of three endocardial lesions were confirmed and corresponded to a decrease in the measured displacement amplitude. PMID:26431798

  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.

  8. 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

  9. Periprocedural anticoagulation of patients undergoing pericardiocentesis for cardiac tamponade complicating catheter ablation of atrial fibrillation.

    PubMed

    Lin, Tao; Bai, Rong; Chen, Ying-wei; Yu, Rong-hui; Tang, Ri-bo; Sang, Cai-hua; Li, Song-nan; Ma, Chang-sheng; Dong, Jian-zeng

    2015-01-01

    Anticoagulation of patients with cardiac tamponade (CT) complicating catheter ablation of atrial fibrillation (AF) is an ongoing problem. The aim of this study was to survey the clinical practice of periprocedural anticoagulation in such patients. This study analyzed the periprocedural anticoagulation of 17 patients with CT complicating AF ablation. Emergent pericardiocentesis was performed once CT was confirmed. The mean drained volume was 410.0 ± 194.1 mL. Protamine sulfate was administered to neutralize heparin (1 mg neutralizes 100 units heparin) in 11 patients with persistent pericardial bleeding and vitamin K1 (10 mg) was given to reverse warfarin in 3 patients with supratherapeutic INR (INR > 2.1). Drainage catheters were removed 12 hours after echocardiography confirmed absence of intrapericardial bleeding and anticoagulation therapy was restored 12 hours after removing the catheter. Fifteen patients took oral warfarin and 10 of them were given subcutaneous injection of LMWH (1 mg/kg, twice daily) as a bridge to resumption of systemic anticoagulation with warfarin. Two patients with a small amount of persistent pericardial effusion were given LMWH on days 5 and 13, and warfarin on days 6 and 24. The dosage of warfarin was adjusted to keep the INR within 2-3 in all patients. After 12 months of follow-up, all patients had no neurological events and no occurrence of delayed CT. The results showed that it was effective and safe to resume anticoagulation therapy 12 hours after removal of the drainage catheter. This may help to prevent thromboembolic events following catheter ablation of AF.

  10. Catheter-Based Ultrasound Applicators for Selective Prostate Ablation With MR-Guidance

    NASA Astrophysics Data System (ADS)

    Diederich, Chris J.; Ross, Anthony B.; Nau, Will H.; Butts, Kim; Rieke, Viola; Sommer, Graham

    2005-03-01

    The purpose of this study was to develop catheter-based ultrasound devices and techniques specifically for treating prostate cancer in conjunction with MRI thermal imaging to monitor and control treatment progression. Directional transurethral applicators have been designed with arrays of sectored tubular (90° active acoustic sector) or narrow planar transducer segments integrated with a flexible delivery catheter with a cooling balloon. Interstitial applicators (2.4 mm catheter diameter, 1.5 mm OD tubular transducers) with 180° active acoustic sectors have been developed specifically for transperineal implantation to treat the posterior portion of the prostate. Both heating strategies were evaluated via in vivo experiments within canine prostate. Both transurethral and interstitial treatment strategies demonstrated significant potential for selective thermal ablation of localized regions of the prostate, particularly when MRI thermal imaging is used to guide and assess treatment.

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

    PubMed Central

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

    2015-01-01

    We developed and evaluated a novel system for guiding radio-frequency catheter ablation therapy of ventricular tachycardia. This guidance system employs an Inverse Solution Guidance Algorithm (ISGA) utilizing 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 one millisecond duration pacing pulses. Signals were recorded from 64 electrodes, located either on the inner surface of the saline-tank or 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 a SEMD inverse algorithm to guide a cardiac ablation catheter. PMID:23448231

  12. Catheter ablation of accessory pathways near the coronary sinus: Value of defining coronary arterial anatomy

    PubMed Central

    Mao, Jessica; Moriarty, John M.; Mandapati, Ravi; Boyle, Noel G.; Shivkumar, Kalyanam; Vaseghi, Marmar

    2015-01-01

    BACKGROUND Accessory pathways can lie near or within the coronary sinus (CS). Radiofrequency catheter ablation of accessory pathways is a well-established treatment option, but this procedure can cause damage to adjacent coronary arteries. OBJECTIVE The purpose of this study was to evaluate the anatomic relationship between the coronary arteries and the CS. METHODS Retrospective data of patients who underwent catheter ablation of supraventricular tachycardia between June 2011 and August 2013 was reviewed. In addition, detailed analysis of coronary computed tomographic angiography (CTA) data from 50 patients was performed. RESULTS Between June 2011 and August 2013, 427 patients underwent catheter ablation of supraventricular tachycardia, of whom 105 (age 28 ± 17 years, 60% male) had accessory pathway–mediated tachycardia. Of these, 23 patients had accessory pathways near the CS, and 60% (N = 14) underwent concurrent coronary angiography. In 4 patients, the posterolateral (inferolateral) branch (PLA) of the right coronary artery was in close proximity to the CS, and 2 patients (18%) had stenosis of the PLA at the site of ablation. On CTA at their closest proximity, the PLA was 1.9 ± 1.3 mm and the left circumflex artery (LCx) was 2.0 ± 0.8 mm from the body of the CS, in right and left coronary artery–dominant patients, respectively. CS ostium and PLA were 3.6 ± 1.9 mm apart. In left-dominant patients, LCx and CS ostium were 3.8 ± 1.2 mm apart. CONCLUSION The PLA and LCx are in close proximity to the anteroinferior aspect of the CS ostium and proximal CS. The relationship of the CS and coronary arteries should be evaluated before ablation at these sites. PMID:25485779

  13. 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.

  14. 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

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

    PubMed

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

    2016-09-01

    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

  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. [Catheter ablation of atrial fibrillation: Health Technology Assessment Report from the Italian Association of Arrhythmology and Cardiac Pacing (AIAC)].

    PubMed

    Themistoclakis, Sakis; Tritto, Massimo; Bertaglia, Emanuele; Berto, Patrizia; Bongiorni, Maria Grazia; Catanzariti, Domenico; De Fabrizio, Giuseppe; De Ponti, Roberto; Grimaldi, Massimo; Pandozi, Claudio; Tondo, Claudio; Gulizia, Michele

    2011-11-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and significantly impact patients' quality of life, morbidity and mortality. The number of affected patients is expected to increase as well as the costs associated with AF management, mainly driven by hospitalizations. Over the last decade, catheter ablation techniques targeting pulmonary vein isolation have demonstrated to be effective in treating AF and preventing AF recurrence. This Health Technology Assessment report of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) aims to define the current role of catheter ablation of AF in terms of effectiveness, efficiency and appropriateness. On the basis of an extensive review of the available literature, this report provides (i) an overview of the epidemiology, clinical impact and socio-economic burden of AF; (ii) an evaluation of therapeutic options other than catheter ablation of AF; and (iii) a detailed presentation of clinical outcomes and cost-benefit ratio associated with catheter ablation. The costs of catheter ablation of AF in Italy were obtained using a bottom-up analysis of a resource utilization survey of 52 hospitals that were considered a representative sample, including 4 Centers that contributed with additional unit cost information in a separate questionnaire. An analysis of budget impact was also performed to evaluate the impact of ablation on the management costs of AF. Results of this analysis show that (1) catheter ablation is effective, safe and superior to antiarrhythmic drug therapy in maintaining sinus rhythm; (2) the cost of an ablation procedure in Italy typically ranges from €8868 to €9455, though current reimbursement remains insufficient, covering only about 60% of the costs; (3) the costs of follow-up are modest (about 8% of total costs); (4) assuming an adjustment of reimbursement to the real cost of an ablation procedure and a 5-10% increase in the annual rate of ablation procedures, after

  18. Materials for Multifunctional Balloon Catheters With Capabilities in Cardiac Electrophysiological Mapping and Ablation Therapy

    PubMed Central

    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.

    2011-01-01

    Development of advanced surgical tools for minimally invasive procedures represents an activity of central importance to improvements in human health. A key materials challenge is in the realization of bio-compatible interfaces between the classes of semiconductor 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 biocompatible materials and devices that integrate directly with the thin elastic membranes of otherwise conventional balloon catheters, to provide multimodal functionality suitable for clinical use. We present sensors for measuring temperature, flow, tactile, optical and electrophysiological data, together with radio frequency (RF) electrodes for controlled, local ablation of tissue. These components connect together in arrayed layouts designed to decouple their operation from large strain deformations associated with deployment and repeated inflation/deflation. Use of such ‘instrumented’ balloon catheter devices in live animal models and in vitro tests illustrates their operation in cardiac ablation therapy. These concepts have the potential for application in surgical systems of the future, not only those based on catheters but also on other platforms, such as surgical gloves. PMID:21378969

  19. 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.

  20. Development of a Novel Shock Wave Catheter Ablation System -The First Feasibility Study in Pigs-

    PubMed Central

    Hasebe, Yuhi; Yamamoto, Hiroaki; Fukuda, Koji; Nishimiya, Kensuke; Hanawa, Kenichiro; Shindo, Tomohiko; Kondo, Masateru; Nakano, Makoto; Wakayama, Yuji; Takayama, Kazuyoshi; Shimokawa, Hiroaki

    2015-01-01

    Introduction Radio-frequency catheter ablation (RFCA) using Joule heat has two fundamental weaknesses: the limited depth of treatment and the risk of thrombus formation. In contrast, focused shock wave (SW) therapy could damage tissues at arbitrary depths without heat generation. Thus, we aimed to develop a SW catheter ablation (SWCA) system that could compensate for the weaknesses of RFCA therapy. Methods and Results We developed a SWCA system where the SW generated by a Q-switched Holmium: yttrium aluminum garnet (YAG) laser beam was reflected by a reflector attached to 14-Fr catheter tip and then was converged onto the focus. We examined the feasibility of our system on pigs in vivo. When applied using the epicardial approach, the SWCA caused persistent spheroidal lesions with mild superficial injury than the RFCA. The lesions were created to a depth based on the focal length (2.0 mm) [2.36 ± 0.45 (SD) mm immediately after procedure, n = 16]. When applied to the atrioventricular (AV) node using the endocardial approach, the SWCA caused junctional escape rhythms in 2 pigs and AV block in 12 pigs (complete AV block in 9) in acute phase (n = 14). Nine of the 14 pigs survived with pacemakers for the long-term study, and the AV block persisted for 12.6 ± 3.9 (SD) days in all surviving pigs. Histological examination showed AV nodal cell body atrophy in the acute phase and fibrotic lesions in the chronic phase. Importantly, no acute or chronic fatal complications were noted. Conclusions Our novel SWCA system could be a promising modality as a non-thermal ablation method to compensate for the weaknesses of RFCA therapy. However, further research and development will be necessary as the current prototype still exhibited the presence of micro-thrombus formation in the animal studies. PMID:25633373

  1. Reduction of radiation exposure in catheter ablation of atrial fibrillation: Lesson learned

    PubMed Central

    De Ponti, Roberto

    2015-01-01

    Over the last decades, the concern for the radiation injury hazard to the patients and the professional staff has increased in the medical community. Since there is no magnitude of radiation exposure that is known to be completely safe, the use of ionizing radiation during medical diagnostic or interventional procedures should be as low as reasonably achievable (ALARA principle). Nevertheless, in cardiovascular medicine, radiation exposure for coronary percutaneous interventions or catheter ablation of cardiac arrhythmias may be high: for ablation of a complex arrhythmia, such as atrial fibrillation, the mean dose can be > 15 mSv and in some cases > 50 mSv. In interventional electrophysiology, although fluoroscopy has been widely used since the beginning to navigate catheters in the heart and the vessels and to monitor their position, the procedure is not based on fluoroscopic imaging. Therefore, non-fluoroscopic three-dimensional systems can be used to navigate electrophysiology catheters in the heart with no or minimal use of fluoroscopy. Although zero-fluoroscopy procedures are feasible in limited series, there may be difficulties in using no fluoroscopy on a routine basis. Currently, a significant reduction in radiation exposure towards near zero-fluoroscopy procedures seems a simpler task to achieve, especially in ablation of complex arrhythmias, such as atrial fibrillation. The data reported in the literature suggest the following three considerations. First, the use of the non-fluoroscopic systems is associated with a consistent reduction in radiation exposure in multiple centers: the more sophisticated and reliable this technology is, the higher the reduction in radiation exposure. Second, the use of these systems does not automatically lead to reduction of radiation exposure, but an optimized workflow should be developed and adopted for a safe non-fluoroscopic navigation of catheters. Third, at any level of expertise, there is a specific learning curve for

  2. Catheter ablation of a monofocal premature ventricular complex triggering idiopathic ventricular fibrillation.

    PubMed

    Takatsuki, S; Mitamura, H; Ogawa, S

    2001-07-01

    A 62 year old man was admitted for evaluation of recurrent episodes of syncope. A surface ECG showed frequent repetitive premature ventricular complexes of right ventricular outflow tract origin. Ventricular fibrillation was inducible by programmed electrical stimulation but otherwise cardiac evaluation was unremarkable. A diagnosis of idiopathic ventricular fibrillation was made and an implantable cardioverter-defibrillator (ICD) was installed. However, spontaneous ventricular fibrillation recurred, requiring repeated ICD discharges. The ventricular fibrillation was reproducibly triggered by a single premature ventricular complex with a specific QRS morphology. Radiofrequency catheter ablation was carried out to eradicate this complex. No ventricular fibrillation has developed after this procedure, and the patient does not require drug treatment.

  3. Catheter ablation of a polymorphic ventricular tachycardia inducing monofocal premature ventricular complex.

    PubMed

    Uemura, Takashi; Yamabe, Hiroshige; Tanaka, Yasuaki; Morihisa, Kenji; Kawano, Hiroaki; Kaikita, Koichi; Sumida, Hitoshi; Sugiyama, Seigo; Ogawa, Hisao

    2008-01-01

    Ventricular tachycardia originating from the right ventricular outflow tract (RVOT) is considered benign, but sometimes it causes polymorphic ventricular tachycardia and ventricular fibrillation, resulting in sudden cardiac death. A 58-year-old woman without structural heart disease was admitted for evaluation of recurrent episodes of syncope. Surface ECG showed frequent repetitive premature ventricular contraction (PVC) of RVOT origin. Polymorphic ventricular tachycardia triggered by the same PVC was documented by Holter ECG during an episode of syncope. Radiofrequency catheter ablation was performed to eradicate this PVC. No polymorphic ventricular tachycardia has developed after the procedure, and the patient has had no recurrence of syncope.

  4. 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

  5. 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

  6. Effect of Substrate Modification in Catheter Ablation of Paroxysmal Atrial Fibrillation

    PubMed Central

    Nam, Gi-Byoung; Jin, Eun-Sun; Choi, HyungOh; Song, Hae-Geun; Kim, Sung-Hwan; Kim, Ki-Hun; Hwang, Eui-Seock; Park, Kyoung-Min; Kim, Jun; Rhee, Kyoung-Suk; Choi, Kee-Joon; Kim, You-Ho

    2012-01-01

    Catheter ablation of atrial fibrillation that targets complex fractionated electrogram sites has been widely applied in the management of persistent atrial fibrillation. The clinical outcomes of pulmonary vein isolation alone and pulmonary vein isolation plus the use of complex fractionated electrogram-guided ablation (CFEA) have not been fully compared in patients with paroxysmal atrial fibrillation. This prospective study included 70 patients with symptomatic paroxysmal atrial fibrillation that remained inducible after pulmonary vein isolation. For radio-frequency catheter ablation, patients were nonrandomly assigned to a control group (pulmonary vein isolation alone, Group 1, n=35) or a CFEA group (pulmonary vein isolation plus additional CFEA, Group 2, n=35). The times to first recurrence of atrial tachyarrhythmias were compared between the 2 groups. In Group 2, CFEA rendered atrial fibrillation noninducible in 16 patients (45.7%) and converted inducible atrial fibrillation into inducible atrial flutters in 12 patients (34.3%). Atrial fibrillation remained inducible in 7 patients (20%) after the combined ablation procedures. After a mean follow-up of 23 months, freedom from recurrence of atrial tachyarrhythmias was significantly higher in Group 2 than in Group 1 (P=0.037). In Group 1, all of the recurrent tachyarrhythmias were atrial fibrillation, whereas regular tachycardia was the major mechanism of recurrent arrhythmias in Group 2 (atrial tachycardia or atrial flutter in 5 of 6 patients and atrial fibrillation in 1 patient). We found that CFEA after pulmonary vein isolation significantly reduced recurrent atrial tachyarrhythmia and might modify the pattern of arrhythmia recurrence in patients with paroxysmal atrial fibrillation. PMID:22719147

  7. 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.

  8. Catheter ablation for cardiac arrhythmias: A 14-year experience with 5330 consecutive patients at the Quebec Heart Institute, Laval Hospital

    PubMed Central

    O’Hara, Gilles E; Philippon, François; Champagne, Jean; Blier, Louis; Molin, Franck; Côté, Jean-Marc; Nault, Isabelle; Sarrazin, Jean-François; Gilbert, Marcel

    2007-01-01

    BACKGROUND: Catheter ablation is a curative treatment with excellent success and minimal complication rates for patients with supraventricular or ventricular arrhythmias. METHODS: The acute outcomes and complications of all catheter ablation procedures for supraventricular and ventricular arrhythmias performed at the Quebec Heart Institute (Sainte-Foy, Quebec) during a 14-year period from January 1, 1993, to December 31, 2006, were prospectively assessed. The ablation procedures were classified according to the arrhythmias induced using standard electrophysiological techniques and definitions. Immediate success and complication rates were prospectively included in the database. RESULTS: A total of 5330 patients had catheter ablation performed at the Institute during the period assessed. The mean (± SD) age of patients was 50±18 years (range four to 97 years), and 2340 patients (44%) were men. Most of the patients were younger than 75 years (group 1), and 487 (9%) were 75 years of age and older (group 2). Indications for ablations were as follows: atrioventricular nodal reentry tachycardia (AVNRT) in 2263 patients, accessory pathways in 1147 patients, atrioventricular node ablation in 803 patients, typical atrial flutter in 377 patients and atrial tachycardia in 160 patients; 580 patients had other ablation procedures. The overall success rates were 81% for atrial tachycardia, 92% for accessory pathways or flutter, and 99% for AVNRT or atrioventricular node ablation. There was no difference in the success rates of the younger (group 1) and older (group 2) patients. Seventy-seven patients (1.4%) had complications, including 11 major events (myocardial infarction in one patient, pulmonary embolism in three patients and permanent pacemaker in seven patients). In patients undergoing AVNRT ablation, two had a permanent pacemaker implanted immediately after the procedure and three had a permanent pacemaker implanted at follow-up. CONCLUSIONS: The results confirm that

  9. Electrophysiology testing and catheter ablation are helpful when evaluating asymptomatic patients with Wolff-Parkinson-White pattern: the pro perspective.

    PubMed

    Pappone, Carlo; Santinelli, Vincenzo

    2015-09-01

    Important advances in the natural history and diagnosis of, and therapy for, asymptomatic Wolff-Parkinson-White (WPW) syndrome have been made in the last decade by our group. These data have necessitated revisiting current practice guidelines to decide on the optimal management of the asymptomatic WPW population. There has also been an emphasis on identifying initially asymptomatic individuals who are at risk by nationwide screening programs using the electrocardiogram for prophylactic catheter ablation to prevent the lifetime risk of sudden cardiac death, particularly in young asymptomatic people, because only a subgroup of them is at high risk, requiring early catheter ablation.

  10. Isolated Disruption of the Right Coronary Artery Following a Steam Pop during Cavotricuspid Linear Ablation with a Contact Force Catheter.

    PubMed

    Brunelli, Michele; Frommhold, Markus; Back, Dieter; Mierzwa, Marco; Lauer, Bernard; Geller, J Christoph

    2016-07-01

    A 70-year-old woman with persistent atrial fibrillation underwent pulmonary vein isolation and linear ablation with a contact sensor catheter. During cavotricuspid isthmus ablation, a steam pop resulted in cardiac tamponade, and the patient developed severe hypotension despite successful pericardial puncture and minimal residual pericardial effusion. Right coronary artery angiography revealed extravasal contrast medium accumulation posterior of the Crux Cordis. Emergent cardiac surgery confirmed isolated disruption of the artery in the absence of additional heart perforation. Although contact sensor catheters may reduce complications, steam pops can still occur and result in dramatic complications. PMID:27378561

  11. 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

  12. Visualization of catheter ablation for atrial fibrillation: Impact of devices and anatomy.

    PubMed

    Benscoter, Mark A; Iaizzo, Paul A

    2015-11-26

    Endocardial access to the left atrium is commonly achieved to treat patients with atrial fibrillation, using different device delivery systems for cardiac ablation. But the large variation in human anatomy presses the limits of existing medical devices. In this unique study, we directly visualized the device-tissue interface in fresh reanimated human hearts using Visible Heart(®) methodologies. Our goal was to better understand any opportunities to improve therapeutic approaches. The visual images obtained in this study (also featured in this article) allow a more intimate grasp of the key steps required in various ablation procedures, as well as some limitations of current device designs. These images show the potential risks of conducting transseptal punctures and the difficulties of placing catheter tips in certain scenarios (e.g., when creating circumferential lesions); they also demonstrate potential problems that could occur while attempting to place catheter tips on such anatomies like the mitral isthmus. In our analysis of these images, we focus on where enhancements are needed to refine device functionality.

  13. Zero-fluoroscopy catheter ablation of severe drug-resistant arrhythmia guided by Ensite NavX system during pregnancy

    PubMed Central

    Chen, Guangzhi; Sun, Ge; Xu, Renfan; Chen, Xiaomei; Yang, Li; Bai, Yang; Yang, Shanshan; Guo, Ping; Zhang, Yan; Zhao, Chunxia; Wang, Dao Wen; Wang, Yan

    2016-01-01

    Abstract Background: Cardiac arrhythmias can occur during pregnancy. Owing to radiation exposure and other uncertain risks for the mother and fetus, catheter ablation has rarely been performed and is often delayed until the postpartum period. We reported 2 pregnant women who were experiencing severe arrhythmias and were successfully ablated without fluoroscopic guidance. We also carried out a literature review of cases of pregnant women who underwent zero-fluoroscopy ablation. Methods and Results: One woman had drug-resistant and poorly tolerated frequent premature ventricular contraction (PVC) and ventricular tachycardia (VT). The other one had persistent and hardly terminated supraventricular tachycardia (SVT) via a right accessory pathway. The 2 patients were successfully underwent zero-fluoroscopy ablation guided by Ensite NavX system. The procedure time was 42 and 71 minutes, respectively. Conclusion: Catheter ablation of SVT or PVC/VT in pregnant patients can be safely and effectively performed with a completely zero-fluoroscopy approach guided by the Ensite NavX system. In the case of a drug refractory, life-threatening arrhythmia during pregnancy, catheter ablation may be considered. PMID:27512864

  14. 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. PMID:23647934

  15. Lone Atrial Fibrillation Is Associated With Impaired Left Ventricular Energetics That Persists Despite Successful Catheter Ablation

    PubMed Central

    Wijesurendra, Rohan S.; Liu, Alexander; Eichhorn, Christian; Ariga, Rina; Levelt, Eylem; Clarke, William T.; Rodgers, Christopher T.; Karamitsos, Theodoros D.; Bashir, Yaver; Ginks, Matthew; Rajappan, Kim; Betts, Tim; Ferreira, Vanessa M.; Neubauer, Stefan

    2016-01-01

    Background: Lone atrial fibrillation (AF) may reflect a subclinical cardiomyopathy that persists after sinus rhythm (SR) restoration, providing a substrate for AF recurrence. To test this hypothesis, we investigated the effect of restoring SR by catheter ablation on left ventricular (LV) function and energetics in patients with AF but no significant comorbidities. Methods: Fifty-three patients with symptomatic paroxysmal or persistent AF and without significant valvular disease, uncontrolled hypertension, coronary artery disease, uncontrolled thyroid disease, systemic inflammatory disease, diabetes mellitus, or obstructive sleep apnea (ie, lone AF) undergoing ablation and 25 matched control subjects in SR were investigated. Magnetic resonance imaging quantified LV ejection fraction (LVEF), peak systolic circumferential strain (PSCS), and left atrial volumes and function, whereas phosphorus-31 magnetic resonance spectroscopy evaluated ventricular energetics (ratio of phosphocreatine to ATP). AF burden was determined before and after ablation by 7-day Holter monitoring; intermittent ECG event monitoring was also undertaken after ablation to investigate for asymptomatic AF recurrence. Results: Before ablation, both LV function and energetics were significantly impaired in patients compared with control subjects (LVEF, 61% [interquartile range (IQR), 52%–65%] versus 71% [IQR, 69%–73%], P<0.001; PSCS, –15% [IQR, –11 to –18%] versus −18% [IQR, –17% to –19%], P=0.002; ratio of phosphocreatine to ATP, 1.81±0.35 versus 2.05±0.29, P=0.004). As expected, patients also had dilated and impaired left atria compared with control subjects (all P<0.001). Early after ablation (1–4 days), LVEF and PSCS improved in patients recovering SR from AF (LVEF, 7.0±10%, P=0.005; PSCS, –3.5±4.3%, P=0.001) but were unchanged in those in SR during both assessments (both P=NS). At 6 to 9 months after ablation, AF burden reduced significantly (from 54% [IQR, 1.5%–100%] to

  16. Catheter-based high-intensity ultrasound for epicardial ablation of the left ventricle: device design and in vivo feasiblity

    NASA Astrophysics Data System (ADS)

    Salgaonkar, Vasant A.; Nazer, Babak; Jones, Peter D.; Tanaka, Yasuaki; Martin, Alastair; Ng, Bennett; Duggirala, Srikant; Diederich, Chris J.; Gerstenfeld, Edward P.

    2015-03-01

    The development and in vivo testing of a high-intensity ultrasound thermal ablation catheter for epicardial ablation of the left ventricle (LV) is presented. Scar tissue can occur in the mid-myocardial and epicardial space in patients with nonischemic cardiomyopathy and lead to ventricular tachycardia. Current ablation technology uses radiofrequency energy, which is limited epicardially by the presence of coronary vessels, phrenic nerves, and fat. Ultrasound energy can be precisely directed to deliver targeted deep epicardial ablation while sparing intervening epicardial nerve and vessels. The proof-of-concept ultrasound applicators were designed for sub-xyphoid access to the pericardial space through a steerable 14-Fr sheath. The catheter consists of two rectangular planar transducers, for therapy (6.4 MHz) and imaging (5 MHz), mounted at the tip of a 3.5-mm flexible nylon catheter coupled and encapsulated within a custom-shaped balloon for cooling. Thermal lesions were created in the LV in a swine (n = 10) model in vivo. The ultrasound applicator was positioned fluoroscopically. Its orientation and contact with the LV were verified using A-mode imaging and a radio-opaque marker. Ablations employed 60-s exposures at 15 - 30 W (electrical power). Histology indicated thermal coagulation and ablative lesions penetrating 8 - 12 mm into the left ventricle on lateral and anterior walls and along the left anterior descending artery. The transducer design enabled successful sparing from the epicardial surface to 2 - 4 mm of intervening ventricle tissue and epicardial fat. The feasibility of targeted epicardial ablation with catheter-based ultrasound was demonstrated.

  17. Korean Atrial Fibrillation (AF) Network: Genetic Variants for AF Do Not Predict Ablation Success

    PubMed Central

    Choi, Eue-Keun; Park, Jae Hyung; Lee, Ji-Young; Nam, Chung Mo; Hwang, Min Ki; Uhm, Jae-Sun; Joung, Boyoung; Ko, Young-Guk; Lee, Moon-Hyoung; Lubitz, Steven A; Ellinor, Patrick T; Pak, Hui-Nam

    2015-01-01

    Background Genomewide association studies have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between top susceptibility loci and AF recurrence after ablation have not been examined in Asian populations. We examined whether the top single nucleotide polymorphisms (SNPs) at chromosomes 4q25 (PITX2), 16q22 (ZFHX3), and 1q21 (KCNN3) were associated with AF in a Korean population and whether these SNPs were associated with clinical outcomes after catheter ablation for AF. Methods and Results We determined the association between 4 SNPs and AF in 1068 AF patients who underwent catheter ablation (74.6% male, aged 57.5±10.9 years, 67.9% paroxysmal AF) and 1068 age- and sex-matched controls. The SNPs at the PITX2 and ZFHX3 loci, but not the KCNN3 locus, were significantly associated with AF (PITX2/rs6843082_G: odds ratio 3.41, 95% CI 2.55 to 4.55, P=1.32×10−16; PITX2/rs2200733_T: odds ratio 2.05, 95% CI 1.66 to 2.53, P=2.20×10−11; ZFHX3/rs2106261_A: odds ratio 2.33, 95% CI 1.87 to 2.91, P=3.75×10−14; KCNN3/rs13376333_T: odds ratio 1.74, 95% CI 0.93 to 3.25, P=0.085). Among those patients who underwent catheter ablation for AF, none of the top AF-associated SNPs were associated with long-term clinical recurrence of AF after catheter ablation. Conclusions SNPs at the PITX2 and ZFHX3 loci were strongly associated with AF in Korean patients. In contrast to prior reports, none of the 4 top AF-susceptibility SNPs predicted clinical recurrence after catheter ablation. PMID:26272656

  18. Patient specific optimization-based treatment planning for catheter-based ultrasound hyperthermia and thermal ablation

    NASA Astrophysics Data System (ADS)

    Prakash, Punit; Chen, Xin; Wootton, Jeffery; Pouliot, Jean; Hsu, I.-Chow; Diederich, Chris J.

    2009-02-01

    to model thermal ablation, including the addition of temperature dependent attenuation, perfusion, and tissue damage. Pilot point control at the target boundaries was implemented to control power delivery to each transducer section, simulating an approach feasible for MR guided procedures. The computer model of thermal ablation was evaluated on representative patient anatomies to demonstrate the feasibility of using catheter-based ultrasound thermal ablation for treatment of benign prostate hyperplasia (BPH) and prostate cancer, and to assist in designing applicators and treatment delivery strategies.

  19. 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.

  20. Intracardiac echocardiography to guide transseptal catheterization for radiofrequency catheter ablation of left-sided accessory pathways: two case reports.

    PubMed

    Citro, Rodolfo; Ducceschi, Valentino; Salustri, Alessandro; Santoro, Michele; Salierno, Michele; Gregorio, Giovanni

    2004-10-08

    Intracardiac echocardiography (ICE) is a useful tool for guiding transseptal puncture during electrophysiological mapping and ablation procedures. Left-sided accessory pathways (LSAP) can be ablated by using two different modalities: retrograde approach through the aortic valve and transseptal approach with puncture of the fossa ovalis. We shall report two cases of LSAP where transcatheter radiofrequency ablation (TCRFA) was firstly attempted via transaortic approach with ineffective results. Subsequently, a transseptal approach under ICE guidance has been performed. During atrial septal puncture ICE was able to locate the needle tip position precisely and provided a clear visualization of the "tenting effect" on the fossa ovalis. ICE allowed a better mapping of the mitral ring and a more effective catheter ablation manipulation and tip contact which resulted in a persistent and complete ablation of the accessory pathway with a shorter time of fluoroscopic exposure. ICE-guided transseptal approach might be a promising modality for TCRFA of LSAP.

  1. 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

  2. Pulmonary vein stenosis complicating radiofrequency catheter ablation for atrial fibrillation: A literature review.

    PubMed

    Edriss, Hawa; Denega, Tatiana; Test, Victor; Nugent, Kenneth

    2016-08-01

    Radiofrequency catheter ablation has become a widely used intervention in the treatment of atrial fibrillation. Pulmonary vein stenosis (PVS) is one of the most serious complications associated with this procedure; the degree of stenosis ranges from mild (<50%) to complete venous occlusion. The natural history of PVS and the risk of progression of existing PVS are uncertain. Symptomatic and/or severe PVS is a serious medical problem and can be easily misdiagnosed since it is an uncommon and relatively new medical problem, often has low clinical suspicion among clinicians, and has a non-specific presentation that mimics other more common respiratory or cardiac diseases. The estimated incidence varies in literature reports from 0% to 42% of ablation procedures, depending on technical aspects of the procedure and operator skill. Most patients with significant PVS remain asymptomatic or have few symptoms. Symptomatic patients usually present with dyspnea, chest pain, or hemoptysis and are usually treated with balloon angioplasty and/or stent placement. Little is known about the long term effect of PV stenosis/occlusion on the pulmonary circulation and the development of pulmonary hypertension. Evolving technology may reduce the frequency of this complication, but long term studies are needed to understand the effect of therapeutic atrial injury and adverse outcomes. This review summarizes the current literature and outlines an approach to the evaluation and management of these patients. PMID:27492534

  3. Catheter ablation of recurrent polymorphic tachycardia: Use of sodium channel blockade to organize the tachycardia: A case report

    PubMed Central

    Saggu, Daljeet Kaur; Nair, Sandeep G.; Shelke, Abhijeet; Yalagudri, Sachin; Narasimhan, Calambur

    2015-01-01

    A 55 year old male presented with recurrent implantable cardioverter defibrillator (ICD) shocks due to polymorphic ventricular tachycardia (PMVT). He had undergone prior catheter ablation for VT three years ago. During the prior attempt he underwent voltage guided substrate ablation. With programmed ventricular extrastimulation (PVES), PMVT was repeatedly induced requiring DC shock. Intravenous procainamide was administered and PVES was repeated which induced sustained monomorphic ventricular tachycardia (MMVT). This VT had pseudo delta waves with maximum deflection index of 0.68, suggestive of epicardial origin. Activation mapping was performed epicardially. Presystolic potentials were recorded in mid anterolateral wall of left ventricular epicardial region. Radiofrequency (RF) ablation at this site terminated the VT. Post ablation there was no inducible tachycardia and patient is free of arrhythmias during 2 years of follow-up. PMID:27479202

  4. Electrophysiology testing and catheter ablation are helpful when evaluating asymptomatic patients with Wolff-Parkinson-White pattern: the con perspective.

    PubMed

    Skanes, Allan C; Obeyesekere, Manoj; Klein, George J

    2015-09-01

    The association between asymptomatic Wolff-Parkinson-White (WPW) syndrome and sudden cardiac death (SCD) has been well documented. The inherent properties of the accessory pathway determine the risk of SCD in WPW, and catheter ablation essentially eliminates this risk. An approach to WPW syndrome is needed that incorporates the patient's individualized considerations into the decision making. Patients must understand that there is a trade-off of a small immediate risk of an invasive approach for elimination of a small lifetime risk of the natural history of asymptomatic WPW. Clinicians can minimize the invasive risk by only performing ablation for patients with at-risk pathways.

  5. 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

  6. Minimal use of fluoroscopy to reduce fetal radiation exposure during radiofrequency catheter ablation of maternal supraventricular tachycardia.

    PubMed

    Raman, Ajay Sundara; Sharma, Saumya; Hariharan, Ramesh

    2015-04-01

    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

  7. 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

  8. Sinus node revisited in the era of electroanatomical mapping and catheter ablation

    PubMed Central

    Sánchez-Quintana, D; Cabrera, J A; Farré, J; Climent, V; Anderson, R H; Ho, S Y

    2005-01-01

    Objective: To study the architecture of the human sinus node to facilitate understanding of mapping and ablative procedures in its vicinity. Methods: The sinoatrial region was examined in 47 randomly selected adult human hearts by histological analysis and scanning electron microscopy. Results: The sinus node, crescent-like in shape, and 13.5 (2.5) mm long, was not insulated by a sheath of fibrous tissue. Its margins were irregular, with multiple radiations interdigitating with ordinary atrial myocardium. The distances from the node to endocardium and epicardium were variable. In 72% of the hearts, the whole nodal body was subepicardial and in 13 specimens (28%) the inner aspect of the nodal body was subendocardial. The nodal body cranial to the sinus nodal artery was more subendocardial than the remaining nodal portion, which was separated from the endocardium by the terminal crest. In 50% of hearts, the most caudal boundaries of the body of the node were at least 3.5 mm from the endocardium. When the terminal crest was > 7 mm thick (13 hearts, 28%), the tail was subepicardial or intramyocardial and at least 3 mm from the endocardium. Conclusions: The length of the node, the absence of an insulating sheath, the presence of nodal radiations, and caudal fragments offer a potential for multiple breakthroughs of the nodal wavefront. The very extensive location of the nodal tissue, the cooling effect of the nodal artery, and the interposing thick terminal crest caudal to this artery have implications for nodal ablation or modification with endocardial catheter techniques. PMID:15657230

  9. A randomized prospective mechanistic cardiac magnetic resonance study correlating catheter stability, late gadolinium enhancement and 3 year clinical outcomes in robotically assisted vs. standard catheter ablation

    PubMed Central

    Arujuna, Aruna; Karim, Rashed; Zarinabad, Niloufar; Gill, Jaspal; Rhode, Kawal; Schaeffter, Tobias; Wright, Matthew; Rinaldi, C. Aldo; Cooklin, Michael; Razavi, Reza; O'Neill, Mark D.; Gill, Jaswinder S.

    2015-01-01

    Aims To prospectively compare cardiac magnetic resonance late gadolinium enhancement (LGE) findings created by standard vs. robotically assisted catheter ablation lesions and correlate these with clinical outcomes. Methods and results Forty paroxysmal atrial fibrillation patients (mean age 54 ± 13.8 years) undergoing first left atrial ablation were randomized to either robotic-assisted navigation (Hansen Sensei® X) or standard navigation. Pre-procedural, acute (24 h post-procedure) and late (beyond 3 months) scans were performed with LGE and T2W imaging sequences and percentage circumferential enhancement around the pulmonary vein (PV) antra were quantified. Baseline pre-procedural enhancements were similar in both groups. On acute imaging, mean % encirclements by LGE and T2W signal were 72% and 80% in the robotic group vs. 60% (P = 0.002) and 76%(P = 0.45) for standard ablation. On late imaging, the T2W signal resolved to baseline in both groups. Late gadolinium enhancement remained the predominant signal with 56% encirclement in the robotic group vs. 45% in the standard group (P = 0.04). At 6 months follow-up, arrhythmia-free patients had an almost similar mean LGE encirclement (robotic 64%, standard 60%, P = 0.45) but in recurrences, LGE was higher in the robotic group (43% vs. 30%, P = 0.001). At mean 3 years follow-up, 1.3 procedures were performed in the robotic group compared with 1.9 (P < 0.001) in the standard to achieve a success rate of 80% vs. 75%. Conclusion Robotically assisted ablation results in greater LGE around the PV antrum. Effective lesions created through improved catheter stability and contact force during initial treatment may have a role in reducing subsequent re-do procedures. PMID:25687748

  10. Predictive value of superficial cultures to anticipate tunneled hemodialysis catheter-related bloodstream infection.

    PubMed

    Bouza, Emilio; Rojas, Loreto; Guembe, María; Marín, Mercedes; Anaya, Fernando; Luño, José; López, Juan M; Muñoz, Patricia

    2014-03-01

    We performed a prospective study in patients with tunneled catheters to assess the validity of Gram stain and superficial culture for anticipating catheter exit-site infection and hemodialysis catheter-related bloodstream infection. The sensitivity and negative predictive value were high, and we succeeded in identifying a subpopulation at low risk of infection.

  11. Value of Implantable Loop Recorders in Monitoring Efficacy of Radiofrequency Catheter Ablation in Atrial Fibrillation

    PubMed Central

    Yang, Ping; Pu, Lijin; Yang, Liuqing; Li, Fang; Luo, Zhiling; Guo, Tao; Hua, Baotong; Li, Shumin

    2016-01-01

    Background The aim of this study was to evaluate the value of the implantable loop recorder (ILR) in diagnosing atrial fibrillation (AF) and assessing the postoperative efficacy of radiofrequency catheter ablation (RFCA). Material/Methods A total of 32 patients who successfully underwent RFCA were selected. These patients discontinued antiarrhythmic medication with no AF recurrence for more than 3 months after RFCA, and underwent ILR placement by a conventional method. The clinical manifestations and information on arrhythmias recorded by the ILR were followed up to assess the efficacy of AF RFCA. Results The mean follow-up period was 24.7±12.5 months. Of 32 patients with ILR information, 27 had successful RFCA and 5 had recurrent AF. The follow-up results obtained by traditional methods showed 29 patients with successful RFCA and 3 with recurrent AF (P<0.05). Among the 18 patients with clinical symptoms, 13 had recorded cardiac arrhythmic events (72.2%) and 5 showed sinus rhythm (27.8%). The ILRs recorded 18 patients with arrhythmic events (56.3%), including 12 cases of atrial arrhythmias, among whom 5 recurred at 9, 12, 16, 17, and 32 months after AF RFCA; there were also 2 patients with ventricular tachycardia (VT) and 4 with bradycardia. Conclusions The value of ILR in assessing the efficacy of AF RFCA was superior to that of traditional methods. ILR can promptly detect asymptomatic AF, and can monitor electrocardiogram features after RFCA, thus providing objective evidence of efficacy. PMID:27518153

  12. Long‐term Outcomes of Catheter Ablation of Atrial Fibrillation: A Systematic Review and Meta‐analysis

    PubMed Central

    Ganesan, Anand N.; Shipp, Nicholas J.; Brooks, Anthony G.; Kuklik, Pawel; Lau, Dennis H.; Lim, Han S.; Sullivan, Thomas; Roberts‐Thomson, Kurt C.; Sanders, Prashanthan

    2013-01-01

    Background In the past decade, catheter ablation has become an established therapy for symptomatic atrial fibrillation (AF). Until very recently, few data have been available to guide the clinical community on the outcomes of AF ablation at ≥3 years of follow‐up. We aimed to systematically review the medical literature to evaluate the long‐term outcomes of AF ablation. Methods and Results A structured electronic database search (PubMed, Embase, Web of Science, Cochrane) of the scientific literature was performed for studies describing outcomes at ≥3 years after AF ablation, with a mean follow‐up of ≥24 months after the index procedure. The following data were extracted: (1) single‐procedure success, (2) multiple‐procedure success, and (3) requirement for repeat procedures. Data were extracted from 19 studies, including 6167 patients undergoing AF ablation. Single‐procedure freedom from atrial arrhythmia at long‐term follow‐up was 53.1% (95% CI 46.2% to 60.0%) overall, 54.1% (95% CI 44.4% to 63.4%) in paroxysmal AF, and 41.8% (95% CI 25.2% to 60.5%) in nonparoxysmal AF. Substantial heterogeneity (I2>50%) was noted for single‐procedure outcomes. With multiple procedures, the long‐term success rate was 79.8% (95% CI 75.0% to 83.8%) overall, with significant heterogeneity (I2>50%).The average number of procedures per patient was 1.51 (95% CI 1.36 to 1.67). Conclusions Catheter ablation is an effective and durable long‐term therapeutic strategy for some AF patients. Although significant heterogeneity is seen with single procedures, long‐term freedom from atrial arrhythmia can be achieved in some patients, but multiple procedures may be required. PMID:23537812

  13. Successful radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia in a patient with dextrocardia due to unilateral pulmonary agenesis: a case report

    PubMed Central

    Aksu, Tolga; Guler, Tumer Erdem; Golcuk, Ebru; Erden, Ismail; Ozcan, Kazım Serhan

    2015-01-01

    Radiofrequency catheter ablation of the slow pathway is considered to be the treatment of choice for patients with atrioventricular nodal reentrant tachycardia. We report a 34-year-old female with mirror image dextrocardia due to unilateral pulmonary agenesis who underwent successful slow pathway ablation for typical atrioventricular nodal reentrant tachycardia. Using contrast injection, cardiac anatomy was identified in a short time and successfully ablated. PMID:25674017

  14. Interactive real-time mapping and catheter ablation of the cavotricuspid isthmus guided by magnetic resonance imaging in a porcine model

    PubMed Central

    Hoffmann, Boris A.; Koops, Andreas; Rostock, Thomas; Müllerleile, Kai; Steven, Daniel; Karst, Roman; Steinke, Mark U.; Drewitz, Imke; Lund, Gunnar; Koops, Susan; Adam, Gerhard; Willems, Stephan

    2010-01-01

    Aims We investigated the feasibility of real-time magnetic resonance imaging (RTMRI) guided ablation of the cavotricuspid isthmus (CTI) by using a MRI-compatible ablation catheter. Methods and results Cavotricuspid isthmus ablation was performed in an interventional RTMRI suite by using a novel 7 French, steerable, non-ferromagnetic ablation catheter in a porcine in vivo model (n = 20). The catheter was introduced and navigated by RTMRI visualization only. Catheter position and movement during manipulation were continuously visualized during the entire intervention. Two porcine prematurely died due to VT/VF. Anatomical completion of the CTI ablation line could be achieved after a mean of 6.3±3 RF pulses (RF energy: 1807±1016.4 Ws/RF pulse, temperature: 55.9±5.9°C) in n = 18 animals. In 15 of 18 procedures (83.3%) a complete CTI block was proven by conventional mapping in the electrophysiological (EP) lab. Conclusion Completely non-fluoroscopic ablation guided by RTMRI using a steerable and non-ferromagnetic catheter is a promising novel technology in interventional electrophysiology. PMID:19897495

  15. Low rate of asymptomatic cerebral embolism and improved procedural efficiency with the novel pulmonary vein ablation catheter GOLD: results of the PRECISION GOLD trial

    PubMed Central

    De Greef, Yves; Dekker, Lukas; Boersma, Lucas; Murray, Stephen; Wieczorek, Marcus; Spitzer, Stefan G.; Davidson, Neil; Furniss, Steve; Hocini, Mélèze; Geller, J. Christoph; Csanádi, Zoltan

    2016-01-01

    Aims This prospective, multicentre study (PRECISION GOLD) evaluated the incidence of asymptomatic cerebral embolism (ACE) after pulmonary vein isolation (PVI) using a new gold multi-electrode radiofrequency (RF) ablation catheter, pulmonary vein ablation catheter (PVAC) GOLD. Also, procedural efficiency of PVAC GOLD was compared with ERACE. The ERACE study demonstrated that a low incidence of ACE can be achieved with a platinum multi-electrode RF catheter (PVAC) combined with procedural manoeuvres to reduce emboli. Methods and results A total of 51 patients with paroxysmal atrial fibrillation (AF) (age 57 ± 9 years, CHA2DS2-VASc score 1.4 ± 1.4) underwent AF ablation with PVAC GOLD. Continuous oral anticoagulation using vitamin K antagonists, submerged catheter introduction, and heparinization (ACT ≥ 350 s prior to ablation) were applied. Cerebral magnetic resonance imaging (MRI) scans were performed within 48 h before and 16–72 h post-ablation. Cognitive function assessed by the Mini-Mental State Exam at baseline and 30 days post-ablation. New post-procedural ACE occurred in only 1 of 48 patients (2.1%) and was not detectable on MRI after 30 days. The average number of RF applications per patient to achieve PVI was lower in PRECISION GOLD (20.3 ± 10.0) than in ERACE (28.8 ± 16.1; P = 0.001). Further, PVAC GOLD ablations resulted in significantly fewer low-power (<3 W) ablations (15 vs. 23%, 5 vs. 10% and 2 vs. 7% in 4:1, 2:1, and 1:1 bipolar:unipolar energy modes, respectively). Mini-Mental State Exam was unchanged in all patients. Conclusion Atrial fibrillation ablation with PVAC GOLD in combination with established embolic lowering manoeuvres results in a low incidence of ACE. Pulmonary vein ablation catheter GOLD demonstrates improved biophysical efficiency compared with platinum PVAC. Trial registration ClinicalTrials.gov NCT01767558. PMID:26826134

  16. Monitoring Central Venous Catheter Resistance to Predict Imminent Occlusion: A Prospective Pilot Study

    PubMed Central

    Wolf, Joshua; Tang, Li; Rubnitz, Jeffrey E.; Brennan, Rachel C.; Shook, David R.; Stokes, Dennis C.; Monagle, Paul; Curtis, Nigel; Worth, Leon J.; Allison, Kim; Sun, Yilun; Flynn, Patricia M.

    2015-01-01

    Background Long-term central venous catheters are essential for the management of chronic medical conditions, including childhood cancer. Catheter occlusion is associated with an increased risk of subsequent complications, including bloodstream infection, venous thrombosis, and catheter fracture. Therefore, predicting and pre-emptively treating occlusions should prevent complications, but no method for predicting such occlusions has been developed. Methods We conducted a prospective trial to determine the feasibility, acceptability, and efficacy of catheter-resistance monitoring, a novel approach to predicting central venous catheter occlusion in pediatric patients. Participants who had tunneled catheters and were receiving treatment for cancer or undergoing hematopoietic stem cell transplantation underwent weekly catheter-resistance monitoring for up to 12 weeks. Resistance was assessed by measuring the inline pressure at multiple flow-rates via a syringe pump system fitted with a pressure-sensing transducer. When turbulent flow through the device was evident, resistance was not estimated, and the result was noted as “non-laminar.” Results Ten patients attended 113 catheter-resistance monitoring visits. Elevated catheter resistance (>8.8% increase) was strongly associated with the subsequent development of acute catheter occlusion within 10 days (odds ratio = 6.2; 95% confidence interval, 1.8–21.5; p <0.01; sensitivity, 75%; specificity, 67%). A combined prediction model comprising either change in resistance greater than 8.8% or a non-laminar result predicted subsequent occlusion (odds ratio = 6.8; 95% confidence interval, 2.0–22.8; p = 0.002; sensitivity, 80%; specificity, 63%). Participants rated catheter-resistance monitoring as highly acceptable. Conclusions In this pediatric hematology and oncology population, catheter-resistance monitoring is feasible, acceptable, and predicts imminent catheter occlusion. Larger studies are required to validate

  17. Pediatric Tachyarrhythmia and Radiofrequency Catheter Ablation: Results From 1993 to 2011

    PubMed Central

    Park, Hyoung-Seob; Hyun, Myung Chul; Kim, Yoon-Nyun

    2012-01-01

    Background and Objectives We performed a retrospective study to elucidate the frequency of tachycardia mechanisms and the characteristics of accessory pathways (APs), confirmed by radiofrequency catheter ablation (RFCA) in pediatric tachycardia. In addition, we analyzed the efficacy and safety of pediatric RFCA. Subjects and Methods The authors retrospectively reviewed the records of a total of 260 patients (aged 2 to 18 years) who had undergone RFCA between August 1993 and July 2011 at two medical centers in Daegu. Results Two hundred and sixty patients underwent 272 RFCAs at less than 18 years of age. Of these 260 patients, 9 patients (3%) were younger than 6 years, and 175 patients (67%) were older than 12 years. The tachycardia mechanisms observed were atrioventricular reentry tachycardia (AVRT) in 175 patients (65%), atrioventricular nodal reentry tachycardia (AVNRT) in 83 patients (30%), ventricular tachycardia in 12 patients (4%), and atrial tachycardia in 2 patients (0.7%). Among the patients with AVRT, there were 94 concealed APs and 81 manifest APs. Left-side APs were more common in concealed APs than in manifest APs (72/94, 77% vs. 33/81, 41%, p<0.001). Sixty-six percent (55/83) of AVNRT cases were located at the M1 and/or M2 sites. Four patients had multiple tachycardia mechanisms (AVNRT+AVRT) and 9 patients had multiple APs. The recurrence rate was 5% (13/272). Of these recurrent cases, 12 patients had AVRT. The overall success rate was 95%. Conclusion Pediatric RFCA provides a good success rate and an acceptable recurrence. In addition, we suggest that the APs location may be associated with concealed or manifest property of APs. PMID:23236324

  18. Patient Characteristics and the Incidence of Radiation-induced Dermatitis Following Radiofrequency Catheter Ablation

    PubMed Central

    Cha, Myung-Jin; Jo, Seong Jin; Cho, Youngjin; Choi, Eue-Keun

    2016-01-01

    Background and Objectives Radiofrequency catheter ablation (RFCA) exposes patients to fixed angle radiation for extended periods of time. We investigated the incidence and characteristics of radiation-induced dermatitis (RID) associated with RFCA. Subjects and Methods We screened 1347 consecutive patients from 2000 to 2011 who underwent RFCA for any indication and reviewed patients with dermatologic issues at the 1-month follow-up. Skin lesions were classified into three groups: most likely RID, probable RID, and possible RID. Results Of the 1347 enrolled patients, 12 (0.89%) experienced dermatologic issues within 1 month after RFCA, including six patients (0.45%) clinically classified as 'most likely RID' and four patients (0.30%) with 'probable RID'. Ten patients, including most likely RID or probable RID patients, developed skin lesions on the right back and upper arm. Skin lesions did not improve without meticulous treatment, and three cases required surgical intervention. We compared the RID group to the remaining 1335 patients (normal group). The mean body mass indices (BMIs) of the RID and normal groups were 29.3 and 23.9 kg/m2, respectively (p<0.001). Radiation exposure times were longer in the RID group (180±31.0 vs. 47±49.9 minutes, p<0.001). We further analyzed 44 patients (6 RID cases and 38 normal patients) that had BMIs >26 kg/m2 and exposure times >115 minutes based on receiver operator characteristic curve analyses. Among the 35 patients without RID, 29 patients (82.9%) did not use biplane fluoroscopy. Conclusions Patients with high BMIs have a higher risk of developing severe RID with increasing fluoroscopy times using biplane fluoroscopy. PMID:27721855

  19. Uninterrupted rivaroxaban vs. uninterrupted vitamin K antagonists for catheter ablation in non-valvular atrial fibrillation

    PubMed Central

    Cappato, Riccardo; Marchlinski, Francis E.; Hohnloser, Stefan H.; Naccarelli, Gerald V.; Xiang, Jim; Wilber, David J.; Ma, Chang-Sheng; Hess, Susanne; Wells, Darryl S.; Juang, George; Vijgen, Johan; Hügl, Burkhard J.; Balasubramaniam, Richard; De Chillou, Christian; Davies, D. Wyn; Fields, L. Eugene; Natale, Andrea

    2015-01-01

    Aims VENTURE-AF is the first prospective randomized trial of uninterrupted rivaroxaban and vitamin K antagonists (VKAs) in patients with non-valvular atrial fibrillation (NVAF) undergoing catheter ablation (CA). Methods and results Trial size was administratively set at 250, the protocol-specified target. Events were independently and blindly adjudicated. We randomly assigned 248 NVAF patients to uninterrupted rivaroxaban (20 mg once-daily) or to an uninterrupted VKA prior to CA and for 4 weeks afterwards. The primary endpoint was major bleeding events after CA. Secondary endpoints included thromboembolic events (composite of stroke, systemic embolism, myocardial infarction, and vascular death) and other bleeding or procedure-attributable events. Patients were 59.5 ± 10 years of age, 71% male, 74% paroxysmal AF, and had a CHA2DS2-VASc score of 1.6. The average total heparin dose used to manage activated clotting time (ACT) was slightly higher (13 871 vs. 10 964 units; P < 0.001) and the mean ACT level attained slightly lower (302 vs. 332 s; P < 0.001) in rivaroxaban and VKA arms, respectively. The incidence of major bleeding was low (0.4%; 1 major bleeding event). Similarly, thromboembolic events were low (0.8%; 1 ischemic stroke and 1 vascular death). All events occurred in the VKA arm and all after CA. The number of any adjudicated events (26 vs. 25), any bleeding events (21 vs. 18), and any other procedure-attributable events (5 vs. 5) were similar. Conclusion In patients undergoing CA for AF, the use of uninterrupted oral rivaroxaban was feasible and event rates were similar to those for uninterrupted VKA therapy. Name of the Trial Registry Clinicaltrials.gov trial registration number is NCT01729871. PMID:25975659

  20. Safety and efficacy of multipolar pulmonary vein ablation catheter vs. irrigated radiofrequency ablation for paroxysmal atrial fibrillation: a randomized multicentre trial

    PubMed Central

    McCready, J.; Chow, A. W.; Lowe, M. D.; Segal, O. R.; Ahsan, S.; de Bono, J.; Dhaliwal, M.; Mfuko, C.; Ng, A.; Rowland, E. R.; Bradley, R. J. W.; Paisey, J.; Roberts, P.; Morgan, J. M.; Sandilands, A.; Yue, A.; Lambiase, P. D.

    2014-01-01

    Aims The current challenge in atrial fibrillation (AF) treatment is to develop effective, efficient, and safe ablation strategies. This randomized controlled trial assesses the medium-term efficacy of duty-cycled radiofrequency ablation via the circular pulmonary vein ablation catheter (PVAC) vs. conventional electro-anatomically guided wide-area circumferential ablation (WACA). Methods and results One hundred and eighty-eight patients (mean age 62 ± 12 years, 116 M : 72 F) with paroxysmal AF were prospectively randomized to PVAC or WACA strategies and sequentially followed for 12 months. The primary endpoint was freedom from symptomatic or documented >30 s AF off medications for 7 days at 12 months post-procedure. One hundred and eighty-three patients completed 12 m follow-up. Ninety-four patients underwent PVAC PV isolation with 372 of 376 pulmonary veins (PVs) successfully isolated and all PVs isolated in 92 WACA patients. Three WACA and no PVAC patients developed tamponade. Fifty-six percent of WACA and 60% of PVAC patients were free of AF at 12 months post-procedure (P = ns) with a significant attrition rate from 77 to 78%, respectively, at 6 months. The mean procedure (140 ± 43 vs. 167 ± 42 min, P<0.0001), fluoroscopy (35 ± 16 vs. 42 ± 20 min, P<0.05) times were significantly shorter for PVAC than for WACA. Two patients developed strokes within 72 h of the procedure in the PVAC group, one possibly related directly to PVAC ablation in a high-risk patient and none in the WACA group (P = ns). Two of the 47 patients in the PVAC group who underwent repeat ablation had sub-clinical mild PV stenoses of 25–50% and 1 WACA patient developed delayed severe PV stenosis requiring venoplasty. Conclusion The pulmonary vein ablation catheter is equivalent in efficacy to WACA with reduced procedural and fluoroscopy times. However, there is a risk of thrombo-embolic and pulmonary stenosis complications which needs to be addressed and prospectively monitored. Clinical

  1. Personnel, equipment, and facilities for electrophysiological and catheter ablation procedures in Europe: results of the European Heart Rhythm Association Survey.

    PubMed

    Estner, Heidi L; Chen, Jian; Potpara, Tatjana; Proclemer, Alessandro; Todd, Derick; Blomström-Lundqvist, Carina

    2014-07-01

    Clinical electrophysiology (EP) and catheter ablation of arrhythmias are rapidly evolving in recent years. More than 50 000 catheter ablations are performed every year in Europe. Emerging indications, an increasing number of procedures, and an expected high quality require national and international standards as well as trained specialists. The purpose of this European Heart Rhythm Association (EHRA) survey was to assess the practice of requirements for EP personnel, equipment, and facilities in Europe. Responses to the questionnaire were received from 52 members of the EHRA research network. The survey involved high-, medium-, and low-volume EP centres, performing >400, 100-399, and under 100 implants per year, respectively. The following topics were explored: (i) EP personnel issues including balance between female and male operators, responsibilities within the EP department, age profiles, role and training of fellows, and EP nurses, (ii) the equipments available in the EP laboratories, (iii) source of patient referrals, and (iv) techniques used for ablation for different procedures including sedation, and peri-procedural use of anticoagulation and antibiotics. The survey reflects the current EP personnel situation characterized by a high training requirement and specialization. Arrhythmia sections are still most often part of cardiology departments and the head of cardiology is seldom a heart rhythm specialist. Currently, the vast majority of EP physicians are men, although in the subgroup of physicians younger than 40 years, the proportion of women is increasing. Uncertainty exists regarding peri-procedural anticoagulation, antibiotic prophylaxis, and the need for sedation during specific procedures. PMID:24966009

  2. A fast slam approach to freehand 3-d ultrasound reconstruction for catheter ablation guidance in the left atrium.

    PubMed

    Koolwal, Aditya B; Barbagli, Federico; Carlson, Christopher R; Liang, David H

    2011-12-01

    We present a method for real-time, freehand 3D ultrasound (3D-US) reconstruction of moving anatomy, with specific application towards guiding the catheter ablation procedure in the left atrium. Using an intracardiac echo (ICE) catheter with a pose (position/orientation) sensor mounted to its tip, we continually mosaic 2D-ICE images of a left atrium phantom model to form a 3D-US volume. Our mosaicing strategy employs a probabilistic framework based on simultaneous localization and mapping (SLAM), a technique commonly used in mobile robotics for creating maps of unexplored environments. The measured ICE catheter tip pose provides an initial estimate for compounding 2D-ICE image data into the 3D-US volume. However, we simultaneously consider the overlap-consistency shared between 2D-ICE images and the 3D-US volume, computing a "corrected" tip pose if need be to ensure spatially-consistent reconstruction. This allows us to compensate for anatomic movement and sensor drift that would otherwise cause motion artifacts in the 3D-US volume. Our approach incorporates 2D-ICE data immediately after acquisition, allowing us to continuously update the registration parameters linking sensor coordinates to 3D-US coordinates. This, in turn, enables real-time localization and display of sensorized therapeutic catheters within the 3D-US volume for facilitating procedural guidance.

  3. A fast slam approach to freehand 3-d ultrasound reconstruction for catheter ablation guidance in the left atrium.

    PubMed

    Koolwal, Aditya B; Barbagli, Federico; Carlson, Christopher R; Liang, David H

    2011-12-01

    We present a method for real-time, freehand 3D ultrasound (3D-US) reconstruction of moving anatomy, with specific application towards guiding the catheter ablation procedure in the left atrium. Using an intracardiac echo (ICE) catheter with a pose (position/orientation) sensor mounted to its tip, we continually mosaic 2D-ICE images of a left atrium phantom model to form a 3D-US volume. Our mosaicing strategy employs a probabilistic framework based on simultaneous localization and mapping (SLAM), a technique commonly used in mobile robotics for creating maps of unexplored environments. The measured ICE catheter tip pose provides an initial estimate for compounding 2D-ICE image data into the 3D-US volume. However, we simultaneously consider the overlap-consistency shared between 2D-ICE images and the 3D-US volume, computing a "corrected" tip pose if need be to ensure spatially-consistent reconstruction. This allows us to compensate for anatomic movement and sensor drift that would otherwise cause motion artifacts in the 3D-US volume. Our approach incorporates 2D-ICE data immediately after acquisition, allowing us to continuously update the registration parameters linking sensor coordinates to 3D-US coordinates. This, in turn, enables real-time localization and display of sensorized therapeutic catheters within the 3D-US volume for facilitating procedural guidance. PMID:22014856

  4. Atrial rhythm influences catheter tissue contact during radiofrequency catheter ablation of atrial fibrillation: comparison of contact force between sinus rhythm and atrial fibrillation.

    PubMed

    Matsuda, Hisao; Parwani, Abdul Shokor; Attanasio, Philipp; Huemer, Martin; Wutzler, Alexander; Blaschke, Florian; Haverkamp, Wilhelm; Boldt, Leif-Hendrik

    2016-09-01

    Catheter tissue contact force (CF) is an important factor for durable lesion formation during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Since CF varies in the beating heart, atrial rhythm during RFCA may influence CF. A high-density map and RFCA points were obtained in 25 patients undergoing RFCA of AF using a CF-sensing catheter (Tacticath, St. Jude Medical). The operators were blinded to the CF information. Contact type was classified into three categories: constant, variable, and intermittent contact. Average CF and contact type were analyzed according to atrial rhythm (SR vs. AF) and anatomical location. A total of 1364 points (891 points during SR and 473 points during AF) were analyzed. Average CFs showed no significant difference between SR (17.2 ± 11.3 g) and AF (17.2 ± 13.3 g; p = 0.99). The distribution of points with an average CF of ≥20 and <10 g also showed no significant difference. However, the distribution of excessive CF (CF ≥40 g) was significantly higher during AF (7.4 %) in comparison with SR (4.2 %; p < 0.05). At the anterior area of the right inferior pulmonary vein (RIPV), the average CF during AF was significantly higher than during SR (p < 0.05). Constant contact was significantly higher during AF (32.2 %) when compared to SR (9.9 %; p < 0.01). Although the average CF was not different between atrial rhythms, constant contact was more often achievable during AF than it was during SR. However, excessive CF also seems to occur more frequently during AF especially at the anterior part of RIPV.

  5. Atrial rhythm influences catheter tissue contact during radiofrequency catheter ablation of atrial fibrillation: comparison of contact force between sinus rhythm and atrial fibrillation.

    PubMed

    Matsuda, Hisao; Parwani, Abdul Shokor; Attanasio, Philipp; Huemer, Martin; Wutzler, Alexander; Blaschke, Florian; Haverkamp, Wilhelm; Boldt, Leif-Hendrik

    2016-09-01

    Catheter tissue contact force (CF) is an important factor for durable lesion formation during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Since CF varies in the beating heart, atrial rhythm during RFCA may influence CF. A high-density map and RFCA points were obtained in 25 patients undergoing RFCA of AF using a CF-sensing catheter (Tacticath, St. Jude Medical). The operators were blinded to the CF information. Contact type was classified into three categories: constant, variable, and intermittent contact. Average CF and contact type were analyzed according to atrial rhythm (SR vs. AF) and anatomical location. A total of 1364 points (891 points during SR and 473 points during AF) were analyzed. Average CFs showed no significant difference between SR (17.2 ± 11.3 g) and AF (17.2 ± 13.3 g; p = 0.99). The distribution of points with an average CF of ≥20 and <10 g also showed no significant difference. However, the distribution of excessive CF (CF ≥40 g) was significantly higher during AF (7.4 %) in comparison with SR (4.2 %; p < 0.05). At the anterior area of the right inferior pulmonary vein (RIPV), the average CF during AF was significantly higher than during SR (p < 0.05). Constant contact was significantly higher during AF (32.2 %) when compared to SR (9.9 %; p < 0.01). Although the average CF was not different between atrial rhythms, constant contact was more often achievable during AF than it was during SR. However, excessive CF also seems to occur more frequently during AF especially at the anterior part of RIPV. PMID:26498938

  6. Acute Safety of an Open-Irrigated Ablation Catheter with 56-Hole Porous Tip for Radiofrequency Ablation of Paroxysmal Atrial Fibrillation: Analysis from 2 Observational Registry Studies

    PubMed Central

    OZA, SAUMIL R; HUNTER, TINA D; BIVIANO, ANGELO B; DANDAMUDI, GOPI; HERWEG, BENGT; PATEL, ANSHUL M; POLLAK, SCOTT J; WANG, HUIJIAN; FISHEL, ROBERT S

    2014-01-01

    Acute Safety from 2 AF Ablation Registries Introduction This report presents safety data on the use of a new open-irrigation radiofrequency ablation (RFA) catheter with a 56-hole porous tip in 742 patients enrolled in 2 US prospective, multicenter observational registry studies representing real-world use of the catheter. Methods This analysis is comprised of patients who underwent RFA of drug-refractory recurrent symptomatic paroxysmal atrial fibrillation (AF). Acute adverse events (AEs) were collected and categorized by seriousness, timing, and relatedness, with 7 days of follow-up data in one study and at least 120 days of data from a 1-year follow-up in the other. Acute serious adverse events (SAEs) that were identified as potentially related to the device and/or procedure were adjudicated by an independent safety committee. Results A total of 30 patients (4.0%) in the combined studies experienced an acute SAE related to the device and/or procedure, which was similar in the subset of patients age 65 and over (4.2%). These SAEs included 1.2% cardiac tamponade/perforation, 0.7% pericarditis, 0.5% pulmonary events, and 0.8% vascular access complications. No myocardial infarction, stroke, transient ischemic attack, or atrioesophageal fistulas within 7 days postprocedure were reported. In the study with extended follow-up, 1 pulmonary vein stenosis and 1 esophageal injury were seen beyond 7 days postprocedure (0.2% each). There were no device or procedure related deaths. Conclusion Results from 2 large observational studies demonstrated that a new porous tip RFA catheter was safe for the treatment of drug refractory, recurrent, symptomatic paroxysmal AF, including treatment of older patients (≥65 years). PMID:24602038

  7. Radiofrequency catheter ablation for idiopathic right ventricular tachycardia with special reference to morphological variation and long-term outcome.

    PubMed Central

    Chinushi, M.; Aizawa, Y.; Takahashi, K.; Kitazawa, H.; Shibata, A.

    1997-01-01

    OBJECTIVE: To assess the long term outcome of radiofrequency (RF) catheter ablation for idiopathic ventricular tachycardia (VT) originating from the outflow tract of the right ventricle, with special reference to the morphological variation in the VT-QRS complexes. PATIENTS: 13 patients whose ventricular tachycardia was treated with RF ablation were followed up more than 18 months after RF ablation. RESULTS: Endocardial mapping revealed the various extensions of ventricular tachycardia origin (from 0.5 x 0.5 cm to 2.0 x 2.0 cm) in which the earliest local electrogram was recorded during ventricular tachycardia. In all five tachycardias from a relatively wider origin (more than 0.5 x 0.5 cm) and in four of eight from a narrow origin (< 0.5 x 0.5 cm), subtle morphological variation in the VT-QRS complexes was observed. In tachycardias with morphological variation, the local electrogram at the tachycardia origin also showed concomitant variation in morphology and activation sequence. Ventricular tachycardia from a narrow site was eliminated by RF ablation to the confined site, but a larger number of RF applications was required in tachycardias from a wider origin. All 13 tachycardias were successfully ablated by RF current, and during the follow up period of 28.2 (SD 7.2) months, recurrence was observed in only one patient who had a wider origin. CONCLUSIONS: Long term efficacy of RF ablation was excellent in idiopathic ventricular tachycardia originating from the outflow tract of the right ventricle. Subtle morphological variations were frequently observed in this type of ventricular tachycardia, and about half of them represented a relatively wider arrhythmogenic area. PMID:9391287

  8. Transient sinus node dysfunction following sinus node artery occlusion due to radiofrequency catheter ablation of the septal superior vena cava-right atrium junction.

    PubMed

    Kitamura, Takeshi; Fukamizu, Seiji; Arai, Ken; Hojo, Rintaro; Aoyama, Yuya; Komiyama, Kota; Sakurada, Harumizu; Hiraoka, Masayasu

    2016-01-01

    We performed catheter ablation to septal superior vena cava (SVC)-right atrium (RA) junction rapid firing in a 57-year-old man with paroxysmal atrial fibrillation. He later experienced transient sinus node dysfunction resulting from injury to the sinus node artery (SNA), which branched only from the proximal region of the left circumflex artery. The direction of the SNA should be considered during catheter ablation at the septal SVC-RA junction, especially if the sinus node is supplied by only one SNA from the right coronary artery or the left circumflex artery.

  9. Catheter Ablation to Treat Supraventricular Arrhythmia in Children and Adults With Congenital Heart Disease: What We Know and Where We Are Going

    PubMed Central

    Thomas, Patricia E.; Macicek, Scott L.

    2016-01-01

    Background: Catheter ablation has been used to manage supraventricular arrhythmia in children since 1990. This article reviews the history of catheter ablation used to treat arrhythmia in children and discusses new frontiers in the field. We also address ablation in adult patients with a history of congenital heart disease (CHD) that was diagnosed and initially treated in childhood. Methods: We conducted an evidence-based literature review to gather available data on ablation for supraventricular tachycardia in children and adult patients with CHD. Results: Ablations can be performed safely and effectively in children. Complication rates are higher in children <4 years and <15 kg. In one study, the overall success rate of radiofrequency ablation in pediatrics was 95.7%, with the highest success rate in left free wall pathways (97.8%). Recurrence was higher in septal pathways. Cryoablation has been reported to have a 93% acute success rate for atrioventricular (AV) nodal reentrant tachycardia and septal pathways with no risk of AV block and a 5%-9% risk of recurrence. Three-dimensional mapping, intracardiac echocardiography, remote magnetic navigation, and irrigated catheter ablation are new technologies used to treat pediatric and adult patients with CHD. The population of adult patients with CHD is growing, and these patients are at particularly high risk for arrhythmia. A paucity of data is available on ablation in adult patients with CHD. Conclusion: Electrophysiology for pediatric and adult patients with CHD is a rapidly growing and progressing field. We benefit from continuous development of ablation techniques for adults with structurally normal hearts and have the unique challenge and responsibility to ensure the safe and effective application of these techniques in the vulnerable population of pediatric and adult patients with CHD.

  10. Catheter Ablation to Treat Supraventricular Arrhythmia in Children and Adults With Congenital Heart Disease: What We Know and Where We Are Going

    PubMed Central

    Thomas, Patricia E.; Macicek, Scott L.

    2016-01-01

    Background: Catheter ablation has been used to manage supraventricular arrhythmia in children since 1990. This article reviews the history of catheter ablation used to treat arrhythmia in children and discusses new frontiers in the field. We also address ablation in adult patients with a history of congenital heart disease (CHD) that was diagnosed and initially treated in childhood. Methods: We conducted an evidence-based literature review to gather available data on ablation for supraventricular tachycardia in children and adult patients with CHD. Results: Ablations can be performed safely and effectively in children. Complication rates are higher in children <4 years and <15 kg. In one study, the overall success rate of radiofrequency ablation in pediatrics was 95.7%, with the highest success rate in left free wall pathways (97.8%). Recurrence was higher in septal pathways. Cryoablation has been reported to have a 93% acute success rate for atrioventricular (AV) nodal reentrant tachycardia and septal pathways with no risk of AV block and a 5%-9% risk of recurrence. Three-dimensional mapping, intracardiac echocardiography, remote magnetic navigation, and irrigated catheter ablation are new technologies used to treat pediatric and adult patients with CHD. The population of adult patients with CHD is growing, and these patients are at particularly high risk for arrhythmia. A paucity of data is available on ablation in adult patients with CHD. Conclusion: Electrophysiology for pediatric and adult patients with CHD is a rapidly growing and progressing field. We benefit from continuous development of ablation techniques for adults with structurally normal hearts and have the unique challenge and responsibility to ensure the safe and effective application of these techniques in the vulnerable population of pediatric and adult patients with CHD. PMID:27660579

  11. Novel balloon catheter device with pacing, ablating, electroporation, and drug-eluting capabilities for atrial fibrillation treatment--preliminary efficacy and safety studies in a canine model.

    PubMed

    DeSimone, Christopher V; Ebrille, Elisa; Syed, Faisal F; Mikell, Susan B; Suddendorf, Scott H; Wahnschaffe, Douglas; Ladewig, Dorothy J; Gilles, Emily J; Danielsen, Andrew J; Holmes, David R; Asirvatham, Samuel J

    2014-12-01

    Pulmonary vein isolation is an established therapeutic procedure for symptomatic atrial fibrillation (AF). This approach involves ablation of atrial tissue just outside the pulmonary veins. However, patient outcomes are limited because of a high rate of arrhythmia recurrence. Ablation of electrically active tissue inside the pulmonary vein may improve procedural success, but is currently avoided because of the complication of postablation stenosis. An innovative device that can ablate inside pulmonary veins and prevent stenosis is a viable strategy to increase long-term efficacy. We have developed a prototypical balloon catheter device capable of nonthermal pulmonary vein ablation along with elution of an antifibrotic agent intended to eliminate arrhythmogenic substrate without the risk of stenosis and have demonstrated its functionality in 4 acute canine experiments. Further optimization of this device may provide an innovative means to simultaneously ablate and prevent pulmonary vein stenosis for improved AF treatment in humans. PMID:25092516

  12. 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.

  13. Combined catheter ablation for atrial fibrillation and Watchman® left atrial appendage occlusion procedures: Five-year experience

    PubMed Central

    Phillips, Karen P.; Walker, Daniel T.; Humphries, Julie A.

    2015-01-01

    Background Patients with atrial fibrillation (AF) may benefit from undergoing concomitant interventions of left atrial catheter ablation and device occlusion of the left atrial appendage (LAA) as a two-pronged strategy for rhythm control and stroke prevention. We report on the outcome of combined procedures in a single center case series over a 5-year timeframe. Methods Ninety-eight patients with non-valvular AF and a mean CHA2DS2-VASc score 2.6±1.0 underwent either first time, or redo pulmonary vein isolation (PVI) procedures, followed by successful implant of a Watchman® device. Results All procedures were generally uncomplicated with a mean case time of 213±40 min. Complete LAA occlusion was achieved at initial implant in 92 (94%) patients. Satisfactory LAA occlusion was achieved in 100% of patients at 12 months, with a complete LAA occlusion rate of 86%. All patients discontinued oral anticoagulation. Persistent late peri-device leaks were more frequently associated with device angulation or shoulder protrusion, and were associated with a significantly lower achieved device compression of 12±3% vs. 15±5% (p<0.01) than complete occlusion. One ischemic stroke was recorded over a mean follow-up time of 802±439 days. Twelve months׳ freedom from detectable AF was achieved in 77% of patients. Conclusions Combined procedures of catheter ablation for AF and Watchman® LAA implant appear to be feasible and safe, with excellent rates of LAA occlusion achieved and an observed stroke rate of 0.5% per year during mid-term follow-up. Incomplete occlusion was associated with lower achieved device compression and was more frequently associated with suboptimal device position. PMID:27092193

  14. Postimplantation X-ray parameters predict functional catheter problems in peritoneal dialysis.

    PubMed

    Bammens, Bert; Peeters, Domien; Jaekers, Joris; Claes, Kathleen J; Evenepoel, Pieter; Kuypers, Dirk; Meijers, Björn; Naesens, Maarten; Vanrenterghem, Yves; Monbaliu, Diethard

    2014-11-01

    Functional catheter problems are a major challenge for peritoneal dialysis (PD) programs. Here we performed a retrospective single-center study of 110 consecutive patients receiving a first PD catheter (swan neck double-cuff Missouri curled catheters, open surgical technique). Using postimplantation X-ray, the following categories were defined: swan neck angle (posterioanterio view (PA): under 45°, 45-90°, over 90°), inclination (angle between intramural part of catheter and horizontal line; lateral view: greater than/equal to 30°, under 30°), and the position of silicone bead relative to spine (PA view: L1-2, L3-4, lower) and catheter tip (PA view: hypogastric, umbilical, subcostal). Covariates included demographics, body size, previous abdominal surgery, and abdominal wall hernias. During a mean follow-up of 36 months, the time to first functional catheter problem was significantly associated with both the swan neck angle and inclination. The need for surgical intervention was significantly associated with inclination only. Technique failure was not associated with any parameter. In multivariate analysis, inclination was the sole variable significantly associated with functional catheter problems (hazard ratio 3.65 [1.98-6.72]) and the need for surgical intervention (hazard ratio 2.86 [1.19-6.88]). Thus, our study defines a set of X-ray variables that predict functional PD catheter problems and can be used for troubleshooting in individual cases as well as for education and internal audit purposes. PMID:24940799

  15. Catheter ablation of non-inducible atrial tachycardia after surgical repair of heart disease.

    PubMed

    Tomita, Takeshi; Aizawa, Kazunori; Takeuchi, Takahiro; Shimada, Kentaro; Okada, Ayako; Koshikawa, Megumi; Kasai, Hiroki; Izawa, Atsushi; Miyashita, Yusuke; Kumazaki, Setsuo; Koyama, Jun; Ikeda, Uichi

    2012-01-01

    We present a patient with non-inducible atrial tachycardia (AT) after atriotomy for surgical repair of heart disease who underwent ablation successfully. Using a 3-D mapping system, we presumed the atriotomy site on the lateral right atrial wall by searching for linear double potentials (DP) during sinus/paced rhythm from the coronary sinus, but it was evaluated incompletely. We could verify the edges of the atriotomy scar precisely by pacing from close to the linear DP lesion and the opposite site. After ablation between the presumed atriotomy scar and the inferior vena cava and cavotricuspid isthmus, no AT recurred without anti-arrhythmic drugs.

  16. Effects of energy delivery via a His bundle catheter during closed chest ablation of the atrioventricular conduction system.

    PubMed Central

    Trantham, J L; Gallagher, J J; German, L D; Broughton, A; Guarnieri, T; Kasell, J

    1983-01-01

    In this paper we summarize our experience and report the characteristics of energy delivery in 23 patients who have undergone closed chest ablation of the normal atrioventricular (AV) conduction system for the treatment of refractory supraventricular arrhythmias. The induction of AV block was achieved by the synchronous delivery of electrical energy with a damped sinusoidal waveform utilizing a standard direct current defibrillator and a standard tripolar His bundle catheter. The procedure was well tolerated, though one patient experienced ventricular fibrillation, which was uneventfully converted with external paddles. Complete AV block was achieved in 20 of 23 patients and all were rendered arrhythmia free, though two still required antiarrhythmic drugs. A stable escape rhythm was seen in all patients with a cycle length of 1,294 +/- 243 ms. Creatine phosphokinase-MB was positive at low levels in 19 of 23 patients and cleared within 24 h. 99mTc pyrophosphate scans were faintly positive in only 2 of 22 patients. Left ventricular wall motion and ejection fractions were unchanged in 19 of 19 patients, two-dimensional echocardiography with microcavitation technique was unchanged in 12 of 12 patients, and a slight increase in pulmonary artery wedge pressure was seen in only 1 of 11 patients. Current, voltage, and their product (power) waveforms were recorded in 12 patients (12 recordings at a defibrillator setting of 200 J and 5 recordings at a defibrillator setting of 300 J) and revealed a complex voltage-current relationship due to changes occurring at the catheter electrode-tissue interface. At 200 J the peak values were 42.2 +/- 3.3 A, 2.16 +/- 0.11 kV, and 87.9 +/- 4.7 kW, while at 300 J the peak values were 58.2 +/- 2.8 A, 2.40 +/- 0.10 kV, and 134.4 +/- 6.7 kW, respectively. No instance of catheter disruption was seen, though "pitting" of the distal electrode (through which current passed) occurred in all but one catheter. Images PMID:6605367

  17. Catheter ablation of persistent atrial fibrillation: The importance of substrate modification

    PubMed Central

    Letsas, Konstantinos P; Efremidis, Michael; Sgouros, Nikolaos P; Vlachos, Konstantinos; Asvestas, Dimitrios; Sideris, Antonios

    2015-01-01

    Accumulating data have shown that elimination of atrial fibrillation (AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms (CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency (DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively “healthy islands” within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes. PMID:25810810

  18. Major complications of cryoballoon catheter ablation for atrial fibrillation and their management.

    PubMed

    Bhat, Tariq; Baydoun, Hassan; Asti, Deepak; Rijal, Jharendra; Teli, Sumaya; Tantray, Mohmad; Bhat, Hilal; Kowalski, Marcin

    2014-09-01

    Atrial fibrillation (AF) is the most common symptomatic and sustained cardiac arrhythmia. It affects approximately 2-3 million people in the USA alone with an increased incidence and prevalence worldwide. It is associated, in addition to worsening quality of life, with increased morbidity and mortality especially in poorly controlled AF, affecting mostly those older than 65 years of age. Radiofrequency ablation was found to be a good strategy for focal isolation of pulmonary veins triggering from the vulnerable atrial substrate but is a time-consuming procedure and carries the risk of multiple complications like tamponade which could be fatal, atrioesophageal fistula and local thrombus formation at the site of ablation. Cryoballoon ablation with pulmonary vein isolation has emerged in the past few years as a breakthrough novel technology for the treatment of drug-refractory AF. It is a relatively simple alternative for point-by-point radiofrequency ablation of paroxysmal AF and is associated with fewer incidences of fatal complications such as cardiac perforation. As experience with this new tool accumulates, the field faces new challenges in the form of rare compilations including gastroparesis, phrenic nerve palsy, atrioesophageal fistula, pulmonary vein stenosis, thromboembolism pericardial effusion, and tamponade. PMID:25115140

  19. Predictive analysis of optical ablation in several dermatological tumoral tissues

    NASA Astrophysics Data System (ADS)

    Fanjul-Vélez, F.; Blanco-Gutiérrez, A.; Salas-García, I.; Ortega-Quijano, N.; Arce-Diego, J. L.

    2013-06-01

    Optical techniques for treatment and characterization of biological tissues are revolutionizing several branches of medical praxis, for example in ophthalmology or dermatology. The non-invasive, non-contact and non-ionizing character of optical radiation makes it specially suitable for these applications. Optical radiation can be employed in medical ablation applications, either for tissue resection or surgery. Optical ablation may provide a controlled and clean cut on a biological tissue. This is particularly relevant in tumoral tissue resection, where a small amount of cancerous cells could make the tumor appear again. A very important aspect of tissue optical ablation is then the estimation of the affected volume. In this work we propose a complete predictive model of tissue ablation that provides an estimation of the resected volume. The model is based on a Monte Carlo approach for the optical propagation of radiation inside the tissue, and a blow-off model for tissue ablation. This model is applied to several types of dermatological tumoral tissues, specifically squamous cells, basocellular and infiltrative carcinomas. The parameters of the optical source are varied and the estimated resected volume is calculated. The results for the different tumor types are presented and compared. This model can be used for surgical planning, in order to assure the complete resection of the tumoral tissue.

  20. FBG Sensor for Contact Level Monitoring and Prediction of Perforation in Cardiac Ablation

    PubMed Central

    Ho, Siu Chun Michael; Razavi, Mehdi; Nazeri, Alireza; Song, Gangbing

    2012-01-01

    Atrial fibrillation (AF) is the most common type of arrhythmia, and is characterized by a disordered contractile activity of the atria (top chambers of the heart). A popular treatment for AF is radiofrequency (RF) ablation. In about 2.4% of cardiac RF ablation procedures, the catheter is accidently pushed through the heart wall due to the application of excessive force. Despite the various capabilities of currently available technology, there has yet to be any data establishing how cardiac perforation can be reliably predicted. Thus, two new FBG based sensor prototypes were developed to monitor contact levels and predict perforation. Two live sheep were utilized during the study. It was observed during operation that peaks appeared in rhythm with the heart rate whenever firm contact was made between the sensor and the endocardial wall. The magnitude of these peaks varied with pressure applied by the operator. Lastly, transmural perforation of the left atrial wall was characterized by a visible loading phase and a rapid signal drop-off correlating to perforation. A possible pre-perforation signal was observed for the epoxy-based sensor in the form of a slight signal reversal (12–26% of loading phase magnitude) prior to perforation (occurring over 8 s). PMID:22368507

  1. Catheter Ablation of Atrial Fibrillation Raises the Plasma Level of NGF-β Which Is Associated with Sympathetic Nerve Activity

    PubMed Central

    Park, Jae Hyung; Wi, Jin; Lee, Da Lyung; Joung, Boyoung; Lee, Moon Hyoung

    2015-01-01

    Purpose The expression of nerve growth factor-β (NGF-β) is related to cardiac nerve sprouting and sympathetic hyper innervation. We investigated the changes of plasma levels of NGF-β and the relationship to follow-up heart rate variability (HRV) after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Materials and Methods This study included 147 patients with AF (117 men, 55.8±11.5 years, 106 paroxysmal AF) who underwent RFCA. The plasma levels of NGF-β were quantified using double sandwich enzyme linked immunosorbent assay method before (NGF-βpre) and 1 hour after RFCA (NGF-βpost-1hr). HRV at pre-procedure (HRVpre), 3 months (HRVpost-3mo), and 1 year post-procedure (HRVpost-1yr) were analyzed and compared with plasma levels of NGF-β. Results 1) The plasma levels of NGF-β significantly increased after RFCA (20.05±11.09 pg/mL vs. 29.60±19.43 pg/mL, p<0.001). The patients who did not show increased NGF-βpost-1hr were older (p=0.023) and had greater left atrial volume index (p=0.028) than those with increased NGF-βpost-1hr. 2) In patients with NGF-βpre >18 pg/mL, low frequency components (LF)/high-frequency components (HF) (p=0.003) and the number of atrial premature contractions (APCs, p=0.045) in HRVpost-3mo were significantly higher than those with ≤18 pg/mL. 3) The LF/HF at HRVpost-3mo was linearly associated with the NGF-βpre (B=4.240, 95% CI 1.114-7.336, p=0.008) and the NGF-βpost-1hr (B=7.617, 95% CI 2.106-13.127, p=0.007). 4) Both NGF-βpre (OR=1.159, 95% CI 1.045-1.286, p=0.005) and NGF-βpost-1hr (OR=1.098, 95% CI 1.030-1.170, p=0.004) were independent predictors for the increase of LF/HF at HRVpost-3mo. Conclusion AF catheter ablation increases plasma level of NGF-β, and high plasma levels of NGF-βpre was associated with higher sympathetic nerve activity and higher frequency of APCs in HRVpost-3mo. PMID:26446633

  2. Catheter Ablation of Right-Sided Accessory Pathways in Adults Using the Three-Dimensional Mapping System: A Randomized Comparison to the Conventional Approach.

    PubMed

    Ma, Yuedong; Qiu, Jia; Yang, Yang; Tang, Anli

    2015-01-01

    Three-dimensional (3D) mapping and navigation systems have been widely used for the ablation of atrial fibrillation and ventricular tachycardia, but the applicability of these systems for the ablation of supraventricular tachycardia (SVT) due to right-sided accessory pathways (RAPs) remains unknown. The goal of this prospective randomized study was to compare the safety, efficiency, and efficacy of nonfluoroscopic and conventional fluoroscopic mapping techniques in guiding catheter ablation of SVT due to RAPs. Of the 393 consecutive patients with SVT who were randomized to receive either conventional fluoroscopic or Ensite NavX mapping-guided ablation, 64 patients with RAPs were included for analysis. Endpoints for ablation were no evidence of RAP conduction and no inducible atrioventricular reentrant tachycardia (AVRT). The 3D group showed fewer ablation pulses and a shorter total ablation time compared to the conventional group, although the acute procedural success did not differ significantly between the two groups. Total procedure time, electrophysiological study time, total fluoroscopy time, and cumulative radiation doses were also significantly reduced in the 3D group. Patients in the conventional group with a right atrium diameter (RAD) ≥ 47 mm required a longer fluoroscopy time. There was no significant difference in the recurrence rates between the two groups over a follow-up period of 3 to 29 months. There were no permanent complications. The 3D mapping system may be a preferred alternative for patients with AVRT due to RAPs, especially for patients with a large RAD (≥ 47 mm).

  3. Catheter Ablation of Right-Sided Accessory Pathways in Adults Using the Three-Dimensional Mapping System: A Randomized Comparison to the Conventional Approach

    PubMed Central

    Tang, Anli

    2015-01-01

    Three-dimensional (3D) mapping and navigation systems have been widely used for the ablation of atrial fibrillation and ventricular tachycardia, but the applicability of these systems for the ablation of supraventricular tachycardia (SVT) due to right-sided accessory pathways (RAPs) remains unknown. The goal of this prospective randomized study was to compare the safety, efficiency, and efficacy of nonfluoroscopic and conventional fluoroscopic mapping techniques in guiding catheter ablation of SVT due to RAPs. Of the 393 consecutive patients with SVT who were randomized to receive either conventional fluoroscopic or Ensite NavX mapping-guided ablation, 64 patients with RAPs were included for analysis. Endpoints for ablation were no evidence of RAP conduction and no inducible atrioventricular reentrant tachycardia (AVRT). The 3D group showed fewer ablation pulses and a shorter total ablation time compared to the conventional group, although the acute procedural success did not differ significantly between the two groups. Total procedure time, electrophysiological study time, total fluoroscopy time, and cumulative radiation doses were also significantly reduced in the 3D group. Patients in the conventional group with a right atrium diameter (RAD) ≥ 47 mm required a longer fluoroscopy time. There was no significant difference in the recurrence rates between the two groups over a follow-up period of 3 to 29 months. There were no permanent complications. The 3D mapping system may be a preferred alternative for patients with AVRT due to RAPs, especially for patients with a large RAD (≥ 47 mm). PMID:26083408

  4. Assessment of myocardial lesion size during in vitro radio frequency catheter ablation.

    PubMed

    He, Ding Sheng; Bosnos, Michael; Mays, Mary Z; Marcus, Frank

    2003-06-01

    We report our experience with a system that utilizes changes in several biophysical characteristics of cardiac tissue to determine lesion formation and to estimate lesion size both on and off-line in vitro during radio frequency (RF) energy delivery. We analyzed the reactive and resistive components of tissue impedance and tracked the change of phase angle during RF ablation. We correlated the amount of tissue damage with these and other biophysical parameters and compared them with off-line analysis. We found that there are irreversible changes in the reactive and resistive components of impedance that occurred during tissue ablation. The irreversible changes of these components are greater in magnitude, and correlate better with the size of lesions than that of impedance alone that is currently used. Numerically, the best single on-line and off-line correlation for combined perpendicular and parallel electrode orientation was with phase angle. On-line and off-line capacitance and susceptance correlations were essentially similar suggesting that they may be useful as lesion size predictors, given these parameter's persistent change without temperature sensitivity. This study indicates that it is technically feasible to assess lesion formation using biophysical parameters. PMID:12814243

  5. Postprocedural Aspiration Test to Predict Adequacy of Dialysis Following Tunneled Catheter Placement

    SciTech Connect

    Smith, Jason C. Sullivan, Kevin L.; Michael, Beckie

    2006-08-15

    The objective of the study was to determine if a timed aspiration technique with a 20-ml syringe can be used to predict adequacy of blood flow in tunneled dialysis catheters. Sixteen patients referred for de novo placement or manipulation of failing tunneled hemodialysis catheters had the time it takes to fill a 20-ml syringe with the plunger fully withdrawn measured to the nearest tenth of a second. These measurements were correlated with flow rates recorded in dialysis just prior to (if failed catheter) and in the following dialysis session with adequacy determined as at least 300 ml/min. Syringe-filling time (22 catheters in 16 patients) was plotted against adequacy of dialysis. The mean time to fill a 20-ml syringe was 2.2 sec, with a range of 1.0-4.7 sec. The mean time to fill syringes for catheters with adequate dialysis was 1.7 {+-} 0.5 sec, and for inadequate catheters, it was 2.8 {+-} 0.8 sec. These differences are statistically significant (p < 0.001). Using a filling time of greater than or equal to 2 sec as a threshold gives the highest sensitivity (100%) for predicting inadequate dialysis while maintaining high specificity (75%). To achieve a specificity of 100%, a 3-sec cutoff would be necessary, but would lead to a sensitivity of only 20%. A simple and objective aspiration technique can be performed at the time of tunneled dialysis catheter placement/manipulation to reasonably predict adequacy of subsequent dialysis.

  6. 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

  7. Simulated evaluation of an intraoperative surface modeling method for catheter ablation by a real phantom simulation experiment

    NASA Astrophysics Data System (ADS)

    Sun, Deyu; Rettmann, Maryam E.; Packer, Douglas; Robb, Richard A.; Holmes, David R.

    2015-03-01

    In this work, we propose a phantom experiment method to quantitatively evaluate an intraoperative left-atrial modeling update method. In prior work, we proposed an update procedure which updates the preoperative surface model with information from real-time tracked 2D ultrasound. Prior studies did not evaluate the reconstruction using an anthropomorphic phantom. In this approach, a silicone heart phantom (based on a high resolution human atrial surface model reconstructed from CT images) was made as simulated atriums. A surface model of the left atrium of the phantom was deformed by a morphological operation - simulating the shape difference caused by organ deformation between pre-operative scanning and intra-operative guidance. During the simulated procedure, a tracked ultrasound catheter was inserted into right atrial phantom - scanning the left atrial phantom in a manner mimicking the cardiac ablation procedure. By merging the preoperative model and the intraoperative ultrasound images, an intraoperative left atrial model was reconstructed. According to results, the reconstruction error of the modeling method is smaller than the initial geometric difference caused by organ deformation. As the area of the left atrial phantom scanned by ultrasound increases, the reconstruction error of the intraoperative surface model decreases. The study validated the efficacy of the modeling method.

  8. 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).

  9. Effective dose analysis of three-dimensional rotational angiography during catheter ablation procedures

    NASA Astrophysics Data System (ADS)

    Wielandts, J.-Y.; Smans, K.; Ector, J.; De Buck, S.; Heidbüchel, H.; Bosmans, H.

    2010-02-01

    There is increasing use of three-dimensional rotational angiography (3DRA) during cardiac ablation procedures. As compared with 2D angiography, a large series of images are acquired, creating the potential for high radiation doses. The aim of the present study was to quantify patient-specific effective doses. In this study, we developed a computer model to accurately calculate organ doses and the effective dose incurred during 3DRA image acquisition. The computer model simulates the exposure geometry and uses the actual exposure parameters, including the variation in tube voltage and current that is realized through the automatic exposure control (AEC). We performed 3DRA dose calculations in 42 patients referred for ablation on the Siemens Axiom Artis DynaCT system (Erlangen, Germany). Organ doses and effective dose were calculated separately for all projections in the course of the C-arm rotation. The influence of patient body mass index (BMI), dose-area product (DAP), collimation and dose per frame (DPF) rate setting on the calculated doses was also analysed. The effective dose was found to be 5.5 ± 1.4 mSv according to ICRP 60 and 6.6 ± 1.8 mSv according to ICRP 103. Effective dose showed an inversely proportional relationship to BMI, while DAP was nearly BMI independent. No simple conversion coefficient between DAP and effective dose could be derived. DPF reduction did not result in a proportional effective dose decrease. These paradoxical findings were explained by the settings of the AEC and the limitations of the x-ray tube. Collimation reduced the effective dose by more than 20%. Three-dimensional rotational angiography is associated with a definite but acceptable radiation dose that can be calculated for all patients separately. Their BMI is a predictor of the effective dose. The dose reduction achieved with collimation suggests that its use is imperative during the 3DRA procedure.

  10. Adenosine-induced atrioventricular block: a rapid and reliable method to assess surgical and radiofrequency catheter ablation of accessory atrioventricular pathways.

    PubMed

    Keim, S; Curtis, A B; Belardinelli, L; Epstein, M L; Staples, E D; Lerman, B B

    1992-04-01

    Adenosine has been shown to inhibit anterograde and retrograde conduction through the atrioventricular (AV) node while having little or no effect on accessory pathway conduction. Its rapid onset of action and short half-life make it particularly suitable for repetitive measurements. In this study, the utility of adenosine was tested in assessing completeness of accessory pathway ablation. Sixteen patients with an accessory pathway were studied (eight surgical ablations, eight catheter ablations with radiofrequency energy). Before ablation, no accessory pathway was sensitive to adenosine. Twelve patients with pre-excitation showed high grade AV node block with maximal pre-excitation on the administration of adenosine during atrial pacing. Four patients with a concealed accessory pathway demonstrated high grade AV block without evidence of latent anterograde accessory pathway conduction. Preablation ventriculoatrial (VA) block was not observed in any of the 16 patients in response to adenosine during ventricular pacing. Immediately after accessory pathway ablation, all patients developed AV and VA block with the administration of adenosine during atrial and ventricular pacing, respectively. These findings were confirmed during follow-up study 1 week later. Atrioventricular block during atrial and ventricular pacing with adenosine affords a reliable and immediate assessment of successful pathway ablation. PMID:1552087

  11. Use of oral gadobenate dimeglumine to visualise the oesophagus during magnetic resonance angiography in patients with atrial fibrillation prior to catheter ablation

    PubMed Central

    2014-01-01

    Background Atrio-oesophageal fistula was first reported as a fatal complication of surgical endocardial and percutaneous endocardial radiofrequency ablation for atrial fibrillation, with an incidence after catheter ablation between 0.03% and 0.5%. Magnetic resonance angiography (MRA) was usually performed to obtain pre-procedural 3D images, used to merging into an electro-anatomical map, guiding step-by-step ablation strategy of AF. Our aim was to find an easy, safe and cost-effective way to enhance the oesophagus during MRA. Methods In 105 consecutive patients, a right-left phase encoding, free breathing, 3D T1 MRA sequence was performed in the axial plane, >24 hours before catheter ablation, using an intravenous injection of gadobenate dimeglumine contrast medium. The oesophagus was enhanced using an oral gel solution of 0.7 mL gadobenate dimeglumine contrast medium mixed with approximately 40 mg thickened water gel, which was swallowed by the patients on the scanning table, immediately before the MRA sequence acquisition. Results The visualisation of the oesophagus was obtained in 104/105 patients and images were successfully merged, as left atrium and pulmonary veins, into an electro-anatomical map, during percutaneous endocardial radiofrequency ablation. All patients tolerated the study protocol and no immediate or late complication was observed with the oral contrast agent administration. The free-breathing MRA sequence used in our protocol took 7 seconds longer than MRA breath-hold conventional sequence. Conclusion Oesophagus visualization with oral gadobenate dimeglumine is feasible for integration of oesophagus anatomy images into the electro-anatomical map during AF ablation, without undesirable side effects and without significantly increasing cost or examination time. PMID:24927953

  12. Catheter ablation of ventricular tachycardia related to a septo-apical left ventricular aneurysm

    PubMed Central

    Rosu, Radu; Cismaru, Gabriel; Muresan, Lucian; Puiu, Mihai; Andronache, Marius; Gusetu, Gabriel; Pop, Dana; Mircea, Petru-Adrian; Zdrenghea, Dumitru

    2015-01-01

    A 60-year-old male patient with previous myocardial infarction (30 years ago) presented to our cardiology department for sustained monomorphic ventricular tachycardia. The patient presented multiple episodes of tachycardia treated by his internal cardiac defibrillator. Radiofrequency ablation was proposed as curative treatment. The mechanism of the ventricular tachycardia was demonstrated by electrophysiological study using three-dimensional mapping system: Carto 3 (Biosense Webster). Ventricular tachycardia was induced either mechanically or by programmed ventricular stimulation. The tachycardia cycle length was 380 msec. The voltage map confirmed the presence of the septo-apical aneurysm with a local voltage < 0.5 mV. Activation mapping revealed a figure-in-8 circuit of VT with the entrance point inside the dense scar and the exit point at the border zone (between the aneurysm and the healthy tissue of the left ventricular septo-apical region). Radiofrequency energy was delivered at the isthmus of the tachycardia rendering it uniducible by programmed ventricular stimulation. PMID:26770613

  13. Multi-sequence magnetic resonance imaging integration framework for image-guided catheter ablation of scar-related ventricular tachycardia

    NASA Astrophysics Data System (ADS)

    Tao, Qian; Milles, Julien; van Huls van Taxis, Carine; Reiber, Johan H. C.; Zeppenfeld, Katja; van der Geest, Rob J.

    2012-02-01

    Catheter ablation is an important option to treat ventricular tachycardias (VT). Scar-related VT is among the most difficult to treat, because myocardial scar, which is the underlying arrhythmogenic substrate, is patient-specific and often highly complex. The scar image from preprocedural late gadolinium enhancement magnetic resonance imaging (LGE- MRI) can provide high-resolution substrate information and, if integrated at the early stage of the procedure, can largely facilitate the procedure with image guidance. In clinical practice, however, early MRI integration is difficult because available integration tools rely on matching the MRI surface mesh and electroanatomical mapping (EAM) points, which is only possible after extensive EAM has been performed. In this paper, we propose to use a priori information on patient posture and a multi-sequence MRI integration framework to achieve accurate MRI integration that can be accomplished at an early stage of the procedure. From the MRI sequences, the left ventricular (LV) geometry, myocardial scar characteristics, and an anatomical landmark indicating the origin of the left main coronary artery are obtained preprocedurally using image processing techniques. Thereby the integration can be realized at the beginning of the procedure after acquiring a single mapping point. The integration method has been evaluated postprocedurally in terms of LV shape match and actual scar match. Compared to the iterative closest point (ICP) method that uses high-intensity mapping (225+/-49 points), our method using one mapping point reached a mean point-to-surface distance of 5.09+/-1.09 mm (vs. 3.85+/-0.60 mm, p<0.05), and scar correlation of -0.51+/-0.14 (vs. -0.50+/-0.14, p=NS).

  14. Effect of eplerenone on maintenance of sinus rhythm after catheter ablation in patients with long-standing persistent atrial fibrillation.

    PubMed

    Ito, Yoko; Yamasaki, Hiro; Naruse, Yoshihisa; Yoshida, Kentaro; Kaneshiro, Takashi; Murakoshi, Nobuyuki; Igarashi, Miyako; Kuroki, Kenji; Machino, Takeshi; Xu, Dongzhu; Kunugita, Fusanori; Sekiguchi, Yukio; Sato, Akira; Tada, Hiroshi; Aonuma, Kazutaka

    2013-04-01

    Several studies have demonstrated a relation between the rennin-angiotensin-aldosterone system and atrial fibrillation (AF), but there are no reports on the effect of eplerenone, a selective aldosterone blocker, on the prevention of AF recurrence after radiofrequency catheter ablation (RFCA). The aim of this study was to evaluate the effects of eplerenone on clinical outcomes after RFCA in patients with long-standing persistent AF. A total of 161 consecutive patients with long-standing persistent AF (sustained AF duration 1 to 20 years, mean 3.4 ± 3.8) who underwent RFCA were investigated. Eplerenone was used in 55 patients and not used in the remaining 106 patients. Other conventional pharmacologic agents, including angiotensin-converting enzyme inhibitors or angiotensin type 1 receptor blockers, were used equally in the 2 groups. After 24 months of follow-up, 47% of the patients were free from AF recurrence. The rate of freedom from AF recurrence was significantly greater in the eplerenone group (60%) than in the noneplerenone group (40%) (p = 0.011). By univariate analysis, the duration of sustained AF (p <0.001), left atrial diameter (p = 0.010), left atrial volume index (p = 0.017), and early AF recurrence (p <0.001) were significantly associated with AF recurrence, and the use of eplerenone was associated with maintenance of sinus rhythm after RFCA (p = 0.022). Multivariate Cox regression analysis showed that longer duration of sustained AF (>3 years) (p <0.001) and early AF recurrence (p <0.001) were significantly associated with AF recurrence, and only eplerenone therapy significantly improved maintenance of sinus rhythm (p = 0.017). In conclusion, eplerenone significantly improved maintenance of sinus rhythm after RFCA in patients with long-standing persistent AF.

  15. Predicting the optimal depth of left-sided central venous catheters in children.

    PubMed

    Kim, H; Jeong, C-H; Byon, H-J; Shin, H K; Yun, T J; Lee, J-H; Park, Y-H; Kim, J-T

    2013-10-01

    The aim of this study was to predict the optimal depth for insertion of a left-sided central venous catheter in children. Using 3D chest computed tomography angiography, we measured the distance from a point where the internal jugular vein is at the superior border of the clavicle, and from a point where the subclavian vein is inferior to the anterior border of the clavicle, to the junction of the superior vena cava and the right atrium in 257 children. Linear regression analysis revealed that the distances correlated with age, weight and height. Simple formulae for the depth of a central venous catheter via the left internal jugular vein (0.07 × height (cm)) and the left subclavian vein (0.08 × height (cm)) were developed to predict placement of the central venous catheter tip at the junction of the superior vena cava with the right atrium. Using these fomulae, the proportion of catheter tips predicted to be correctly located was 98.5% (95% CI 96.8-100%) and 94.0% (95% CI 90.8-97.3%), respectively.

  16. Successful radiofrequency catheter ablation of a right posterolateral bypass tract in a patient with Wolff-Parkinson-White syndrome after a previous failed ablative procedure: taking the high road.

    PubMed

    Cohen, T J

    2000-07-01

    A 16-year-old high school basketball player with symptomatic Wolff-Parkinson-White syndrome underwent an unsuccessful radiofrequency catheter ablative procedure from the femoral venous approach. During this procedure, the patient received 30 applications of radiofrequency energy without injury to the accessory pathway. The patient was treated with flecinide 100 mg orally twice daily and rescheduled for a second ablative procedure via the right internal jugular venous approach. At the second session, prior to any right internal jugular venous applications, 3 additional applications were delivered via the right femoral venous approach using a different catheter, without success. A single radiofrequency energy application from the right internal jugular venous approach eliminated the bypass tract in approximately 2 seconds. The superior approach achieved a more stable catheter position thereby eliminating the bypass tract. In conclusion, an alternative plan of attack should be considered after multiple failures from a given approach. In other words, take the high road if you can't take the low road.

  17. :Influence of the duration of Holter monitoring on the detection of arrhythmia recurrences after catheter ablation of atrial fibrillation: implications for patient follow-up.

    PubMed

    Dagres, Nikolaos; Kottkamp, Hans; Piorkowski, Christopher; Weis, Sebastian; Arya, Arash; Sommer, Philipp; Bode, Kerstin; Gerds-Li, Jin-Hong; Kremastinos, Dimitrios Th; Hindricks, Gerhard

    2010-03-18

    We investigated the influence of Holter duration on the detection of recurrences after ablation for atrial fibrillation (AF). Two-hundred-and-fifteen patients underwent a 7-day Holter ECG at 6 months after catheter ablation. We analyzed the number of patients who had a recurrence within the first 24, 48, 72 h etc. up to the total of 7 days. During the complete 7-day recording, 30% had a recurrence. All Holter durations ≤5 days would have detected significantly less patients with recurrence than the complete 7-day recording. A 24-hour Holter would have detected 59%, a 48-hour Holter 67% and a 72-hour Holter 80% of patients with recurrences, whereas a 4-day recording would have detected 91% of the recurrences that were detected with the complete 7-day recording. In conclusion, a Holter duration of less than 4 days misses a great portion of recurrences, whereas a 4-day recording might offer a reasonable compromise.

  18. Renal sympathetic denervation as an adjunct to catheter ablation for the treatment of ventricular electrical storm in the setting of acute myocardial infarction.

    PubMed

    Hoffmann, Boris A; Steven, Daniel; Willems, Stephan; Sydow, Karsten

    2013-10-01

    We present a case of ventricular storm (VS) in a patient with acute ST-elevation myocardial infarction (STEMI). After initial successful thrombus extraction and percutaneous coronary intervention (PCI) of the proximal left anterior descending (LAD) coronary artery, a 63-year-old male patient showed recurrent monomorphic ventricular tachycardia (VT) and fibrillation (VF) episodes refractory to antiarrhythmic drug therapy. After initial successful VT ablation, fast VT and VF episodes remained an evident problem despite maximum antiarrhythmic drug therapy. Due to an increasing instability, renal sympathetic denervation (RDN) was performed. ICD interrogation and 24-hour Holter monitoring excluded recurrent episodes of VT or VF at a 6-month follow-up (FU) after discharge. This case highlights that RDN was effective and safely performed in a hemodynamically unstable patient with VS after STEMI and adjunct catheter ablation. RDN may open a new avenue for an adjunctive interventional bailout treatment of such highly challenging patients.

  19. Urinary catheters

    MedlinePlus

    Catheter - urine; Foley catheter; Indwelling catheter; Suprapubic catheters ... many sizes, materials (latex, silicone, Teflon™), and types (Foley, straight, coude tip). A Foley catheter, for example, ...

  20. Patency of Femoral Tunneled Hemodialysis Catheters and Factors Predictive of Patency Failure

    SciTech Connect

    Burton, Kirsteen R.; Guo, Lancia L. Q.; Tan, Kong T.; Simons, Martin E.; Sniderman, Kenneth W.; Kachura, John R.; Beecroft, John R.; Rajan, Dheeraj K.

    2012-12-15

    Purpose: To determine the patency rates of and factors associated with increased risk of patency failure in patients with femoral vein tunneled hemodialysis catheters. Methods: All femoral tunneled catheter insertions from 1996 to 2006 were reviewed, during which time 123 catheters were inserted. Of these, 66 were exchanges. Patients with femoral catheter failure versus those with femoral catheter patency were compared. Confounding factors, such as demographic and procedural factors, were incorporated and assessed using univariate and multivariable Cox proportional hazards regression analyses. Results: Mean catheter primary patency failure time was 96.3 days (SE 17.9 days). Primary patency at 30, 60, 90, and 180 days was 53.8%, 45.4%, 32.1%, and 27.1% respectively. Crude rates of risk of catheter failure did not suggest a benefit for patients receiving catheters introduced from one side versus the other, but more cephalad location of catheter tip was associated with improved patency. Multivariate analysis showed that patients whose catheters were on the left side (p = 0.009), were of increasing age at the time of insertion (p = 0.002) and that those who had diabetes (p = 0.001) were at significantly greater risk of catheter failure. The catheter infection rate was 1.4/1000 catheter days. Conclusion: Patients who were of a more advanced age and had diabetes were at greater risk of femoral catheter failure, whereas those who received femoral catheters from the right side were less at risk of catheter failure.

  1. Low Left Atrial Compliance Contributes to the Clinical Recurrence of Atrial Fibrillation after Catheter Ablation in Patients with Structurally and Functionally Normal Heart

    PubMed Central

    Park, Junbeom; Yang, Pil-sung; Kim, Tae-Hoon; Uhm, Jae-Sun; Kim, Joung-Youn; Joung, Boyoung; Lee, Moon-Hyoung; Hwang, Chun; Pak, Hui-Nam

    2015-01-01

    Stiff left atrial (LA) syndrome was initially reported in post-cardiac surgery patients and known to be associated with low LA compliance. We investigated the physiological and clinical implications of LA compliance by estimating LA pulse pressure (LApp) among patients with atrial fibrillation (AF) and structurally and functionally normal heart. Among 1038 consecutive patients with LA pressure measurements before AF ablation, we included 334 patients with structurally and functionally normal heart (81.7% male, 54.1±10.6 years, 77.0% paroxysmal AF) after excluding those with hypertension, diabetes, and previous ablation or cardiac surgery. We measured LApp (peak-nadir LA pressure) at the beginning of the ablation procedure and compared the values with clinical parameters and the AF recurrence rate.AF patients with normal heart were younger and more frequently male and had paroxysmal AF, a lower body mass index, and a lower LApp compared to others (all p<0.05).Based on the median value, the low LA compliance group (LApp≥13mmHg) had a smaller LA volume index and lower LA voltage (all p<0.05) compared to the high LA compliance group. During a mean follow-up of 16.7±11.8 months, low LA compliance was independently associated with two fold-higher risk of clinical AF recurrence (HR:2.202; 95%CI:1.077–4.503; p = 0.031).Low LA compliance, as determined by an elevated LApp, was associated with a smaller LA volume index and lower LA voltage and independently associated with higher clinical recurrence after catheter ablation in AF patients with structurally and functionally normal heart. PMID:26624617

  2. Catheter-based renal denervation for resistant hypertension: 12-month results of the EnligHTN I first-in-human study using a multielectrode ablation system.

    PubMed

    Papademetriou, Vasilios; Tsioufis, Costas P; Sinhal, Ajay; Chew, Derek P; Meredith, Ian T; Malaiapan, Yuvi; Worthley, Matthew I; Worthley, Stephen G

    2014-09-01

    Renal denervation has emerged as a novel approach for the treatment of patients with drug-resistant hypertension. To date, only limited data have been published using multielectrode radiofrequency ablation systems. In this article, we present the 12-month data of EnligHTN I, a first-in-human study using a multielectrode ablation catheter. EnligHTN I enrolled 46 patients (average age, 60±10 years; on average 4.7±1.0 medications) with drug-resistant hypertension. Eligible patients were on ≥3 antihypertensive medications and had a systolic blood pressure (BP) ≥160 mm Hg (≥150 mm Hg for diabetics). Bilateral renal artery ablation was performed using a percutaneous femoral approach and standardized techniques. The average baseline office BP was 176/96 mm Hg, average 24-hour ambulatory BP was 150/83 mm Hg, and average home BP was 158/90 mm Hg. The average reductions (mm Hg) at 1, 3, 6, and 12 months were as follows: office: -28/-10, -27/-10, -26/-10, and -27/-11 mm Hg (P<0.001 for all); 24-hour ambulatory: -10/-5, -10/-5, -10/-6 (P<0.001 for all), and -7/-4 for 12 months (P<0.0094). Reductions in home measurements (based on 2-week average) were -9/-4, -8/-5,-10/-7, and -11/-6 mm Hg (P<0.001 at 12 months). At 12 months, there were no signals of worsening renal function and no new serious or life-threatening adverse events. One patient with baseline nonocclusive renal artery stenosis progressed to 75% diameter stenosis, requiring renal artery stenting. The 12-month data continue to demonstrate safety and efficacy of the EnligHTN ablation system in patients with drug-resistant hypertension. Home BP measurements parallel measurements obtained with 24-hour ambulatory monitoring.

  3. High positive predictive value of Gram stain on catheter-drawn blood samples for the diagnosis of catheter-related bloodstream infection in intensive care neonates.

    PubMed

    Deleers, M; Dodémont, M; Van Overmeire, B; Hennequin, Y; Vermeylen, D; Roisin, S; Denis, O

    2016-04-01

    Catheter-related bloodstream infections (CRBSIs) remain a leading cause of healthcare-associated infections in preterm infants. Rapid and accurate methods for the diagnosis of CRBSIs are needed in order to implement timely and appropriate treatment. A retrospective study was conducted during a 7-year period (2005-2012) in the neonatal intensive care unit of the University Hospital Erasme to assess the value of Gram stain on catheter-drawn blood samples (CDBS) to predict CRBSIs. Both peripheral samples and CDBS were obtained from neonates with clinically suspected CRBSI. Gram stain, automated culture and quantitative cultures on blood agar plates were performed for each sample. The paired quantitative blood culture was used as the standard to define CRBSI. Out of 397 episodes of suspected CRBSIs, 35 were confirmed by a positive ratio of quantitative culture (>5) or a colony count of CDBS culture >100 colony-forming units (CFU)/mL. All but two of the 30 patients who had a CDBS with a positive Gram stain were confirmed as having a CRBSI. Seven patients who had a CDBS with a negative Gram stain were diagnosed as CRBSI. The sensitivity, specificity, positive predictive value and negative predictive value of Gram stain on CDBS were 80, 99.4, 93.3 and 98.1 %, respectively. Gram staining on CDBS is a viable method for rapidly (<1 h) detecting CRBSI without catheter withdrawal. PMID:26864043

  4. High positive predictive value of Gram stain on catheter-drawn blood samples for the diagnosis of catheter-related bloodstream infection in intensive care neonates.

    PubMed

    Deleers, M; Dodémont, M; Van Overmeire, B; Hennequin, Y; Vermeylen, D; Roisin, S; Denis, O

    2016-04-01

    Catheter-related bloodstream infections (CRBSIs) remain a leading cause of healthcare-associated infections in preterm infants. Rapid and accurate methods for the diagnosis of CRBSIs are needed in order to implement timely and appropriate treatment. A retrospective study was conducted during a 7-year period (2005-2012) in the neonatal intensive care unit of the University Hospital Erasme to assess the value of Gram stain on catheter-drawn blood samples (CDBS) to predict CRBSIs. Both peripheral samples and CDBS were obtained from neonates with clinically suspected CRBSI. Gram stain, automated culture and quantitative cultures on blood agar plates were performed for each sample. The paired quantitative blood culture was used as the standard to define CRBSI. Out of 397 episodes of suspected CRBSIs, 35 were confirmed by a positive ratio of quantitative culture (>5) or a colony count of CDBS culture >100 colony-forming units (CFU)/mL. All but two of the 30 patients who had a CDBS with a positive Gram stain were confirmed as having a CRBSI. Seven patients who had a CDBS with a negative Gram stain were diagnosed as CRBSI. The sensitivity, specificity, positive predictive value and negative predictive value of Gram stain on CDBS were 80, 99.4, 93.3 and 98.1 %, respectively. Gram staining on CDBS is a viable method for rapidly (<1 h) detecting CRBSI without catheter withdrawal.

  5. A case of premature ventricular contractions, ventricular tachycardia, and arrhythmic storm induced by right ventricular pacing during cardiac resynchronization therapy: Electrophysiological mechanism and catheter ablation

    PubMed Central

    Pedretti, Stefano; Vargiu, Sara; Paolucci, Marco; Lunati, Maurizio

    2015-01-01

    A 77-year-old man with ischemic cardiomyopathy and a cardiac resynchronization therapy-defibrillator (CRT-D) device came to our attention due to incessant ventricular tachycardia and multiple implantable cardioverter defibrillator (ICD) shocks. An electrocardiogram showed non-sustained monomorphic ventricular tachycardias (NSVTs) constantly occurring after each biventricular stimulation. During an electrophysiological study, NSVTs reproducibly recurred only after right ventricular (RV) pacing; LV pacing did not induce any NSVTs. The activation map was consistent with a localized reentry at the interventricular septum, and a double exit; at the LV exit site, a single radiofrequency energy application immediately interrupted the occurrence of the NSVTs. Current evidence supports LV pacing to be pro-arrhythmogenic in few CRT patients. This unusual case shows that RV pacing during CRT could produce frequent ventricular arrhythmias and arrhythmic storm. Catheter ablation can be considered an effective therapeutic option, especially when CRT maintenance is highly advisable. PMID:26702324

  6. Spike rate of multi-unit muscle sympathetic nerve fibers following catheter-based renal nerve ablation

    PubMed Central

    Tank, Jens; Heusser, Karsten; Brinkmann, Julia; Schmidt, Bernhard M.; Menne, Jan; Bauersachs, Johann; Haller, Hermann; Diedrich, André; Jordan, Jens

    2016-01-01

    Patients with treatment-resistant arterial hypertension exhibited profound reductions in single sympathetic vasoconstrictor fiber firing rates following renal nerve ablation. In contrast, integrated multi-unit muscle sympathetic nerve activity (MSNA) changed little or not at all. We hypothesized that conventional MSNA analysis may have missed single fiber discharges, thus, obscuring sympathetic inhibition following renal denervation. We studied patients with difficult to control arterial hypertension (age 45–74 years) before, 6 (n=11), and 12 months (n=8) following renal nerve ablation. Electrocardiogram, respiration, brachial, and finger arterial blood pressure (BP), as well as the MSNA raw MSNA signal were analyzed. We detected MSNA action potential spikes using 2 stage kurtosis wavelet denoising techniques to assess mean, median, and maximum spike rates for each beat-to-beat interval. Supine heart rate and systolic BP did not change at 6 (ΔHR: −2±3 bpm; ΔSBP: 2±9 mmHg) or at 12 months (ΔHR: −1±3 mmHg, ΔSBP: −1±9 mmHg) after renal nerve ablation. Mean burst frequency and mean spike frequency at baseline were 34±3 bursts per minute and 8±1 spikes per sec. Both measurements did not change at 6 months (−1.4±3.6 bursts/minute; −0.6±1.4 spikes per sec) or at 12 months (−2.5±4.0 bursts/minute; −2.0±1.6 spikes per sec) following renal nerve ablation. After renal nerve ablation, BP decreased in 3 out of 11 patients. BP and MSNA spike frequency changes were not correlated (slope=−0.06; p=0.369). Spike rate analysis of multi-unit MSNA neurograms further suggests that profound sympathetic inhibition is not a consistent finding following renal nerve ablation. PMID:26324745

  7. Spike rate of multi-unit muscle sympathetic nerve fibers after catheter-based renal nerve ablation.

    PubMed

    Tank, Jens; Heusser, Karsten; Brinkmann, Julia; Schmidt, Bernhard M; Menne, Jan; Bauersachs, Johann; Haller, Hermann; Diedrich, André; Jordan, Jens

    2015-10-01

    Patients with treatment-resistant arterial hypertension exhibited profound reductions in single sympathetic vasoconstrictor fiber firing rates after renal nerve ablation. In contrast, integrated multi-unit muscle sympathetic nerve activity (MSNA) changed little or not at all. We hypothesized that conventional MSNA analysis may have missed single fiber discharges, thus, obscuring sympathetic inhibition after renal denervation. We studied patients with difficult-to-control arterial hypertension (age 45-74 years) before, 6 (n = 11), and 12 months (n = 8) after renal nerve ablation. Electrocardiogram, respiration, brachial, and finger arterial blood pressure (BP), as well as the MSNA and raw MSNA signals were analyzed. We detected MSNA action-potential spikes using 2 stage kurtosis wavelet denoising techniques to assess mean, median, and maximum spike rates for each beat-to-beat interval. Supine heart rate and systolic BP did not change at 6 (ΔHR: -2 ± 3 bpm; ΔSBP: 2 ± 9 mm Hg) or at 12 months (ΔHR: -1 ± 3 mm Hg, ΔSBP: -1 ± 9 mm Hg) after renal nerve ablation. Mean burst frequency and mean spike frequency at baseline were 34 ± 3 bursts per minute and 8 ± 1 spikes per second. Both measurements did not change at 6 months (-1.4 ± 3.6 bursts/minute; -0.6 ± 1.4 spikes/second) or at 12 months (-2.5 ± 4.0 bursts/minute; -2.0 ± 1.6 spikes/second) after renal nerve ablation. After renal nerve ablation, BP decreased in 3 of 11 patients. BP and MSNA spike frequency changes were not correlated (slope = -0.06; P = .369). Spike rate analysis of multi-unit MSNA neurograms further suggests that profound sympathetic inhibition is not a consistent finding after renal nerve ablation. PMID:26324745

  8. Near zerO fluoroscopic exPosure during catheter ablAtion of supRavenTricular arrhYthmias: the NO-PARTY multicentre randomized trial

    PubMed Central

    Casella, Michela; Dello Russo, Antonio; Pelargonio, Gemma; Del Greco, Maurizio; Zingarini, Gianluca; Piacenti, Marcello; Di Cori, Andrea; Casula, Victor; Marini, Massimiliano; Pizzamiglio, Francesca; Zucchetti, Martina; Riva, Stefania; Russo, Eleonora; Narducci, Maria Lucia; Soldati, Ezio; Panchetti, Luca; Startari, Umberto; Bencardino, Gianluigi; Perna, Francesco; Santangeli, Pasquale; Di Biase, Luigi; Cichocki, Fabrizio; Fattore, Giovanni; Bongiorni, Mariagrazia; Picano, Eugenio; Natale, Andrea; Tondo, Claudio

    2016-01-01

    Aims Aim of this study was to compare a minimally fluoroscopic radiofrequency catheter ablation with conventional fluoroscopy-guided ablation for supraventricular tachycardias (SVTs) in terms of ionizing radiation exposure for patient and operator and to estimate patients' lifetime attributable risks associated with such exposure. Methods and results We performed a prospective, multicentre, randomized controlled trial in six electrophysiology (EP) laboratories in Italy. A total of 262 patients undergoing EP studies for SVT were randomized to perform a minimally fluoroscopic approach (MFA) procedure with the EnSiteTMNavXTM navigation system or a conventional approach (ConvA) procedure. The MFA was associated with a significant reduction in patients' radiation dose (0 mSv, iqr 0–0.08 vs. 8.87 mSv, iqr 3.67–22.01; P < 0.00001), total fluoroscopy time (0 s, iqr 0–12 vs. 859 s, iqr 545–1346; P < 0.00001), and operator radiation dose (1.55 vs. 25.33 µS per procedure; P < 0.001). In the MFA group, X-ray was not used at all in 72% (96/134) of cases. The acute success and complication rates were not different between the two groups (P = ns). The reduction in patients' exposure shows a 96% reduction in the estimated risks of cancer incidence and mortality and an important reduction in estimated years of life lost and years of life affected. Based on economic considerations, the benefits of MFA for patients and professionals are likely to justify its additional costs. Conclusion This is the first multicentre randomized trial showing that a MFA in the ablation of SVTs dramatically reduces patients' exposure, risks of cancer incidence and mortality, and years of life affected and lost, keeping safety and efficacy. Trial registration clinicaltrials.gov Identifier: NCT01132274. PMID:26559916

  9. Remote magnetic with open-irrigated catheter vs. manual navigation for ablation of atrial fibrillation: a systematic review and meta-analysis.

    PubMed

    Proietti, Riccardo; Pecoraro, Valentina; Di Biase, Luigi; Natale, Andrea; Santangeli, Pasquale; Viecca, Maurizio; Sagone, Antonio; Galli, Alessio; Moja, Lorenzo; Tagliabue, Ludovica

    2013-09-01

    The aim of this study was to determine the efficacy and safety of remote magnetic navigation (RMN) with open-irrigated catheter vs. manual catheter navigation (MCN) in performing atrial fibrillation (AF) ablation. We searched in PubMed (1948-2013) and EMBASE (1974-2013) studies comparing RMN with MCN. Outcomes considered were AF recurrence (primary outcome), pulmonary vein isolation (PVI), procedural complications, and data on procedure's performance. Odds ratios (OR) and mean difference (MD) were extracted and pooled using a random-effect model. Confidence in the estimates of the obtained effects (quality of evidence) was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. We identified seven controlled trials, six non-randomized and one randomized, including a total of 941 patients. Studies were at high risk of bias. No difference was observed between RMN and MCN on AF recurrence [OR 1.18, 95% confidence interval (CI) 0.85 to 1.65, P = 0.32] or PVI (OR 0.41, 95% CI 0.11-1.47, P = 0.17). Remote magnetic navigation was associated with less peri-procedural complications (Peto OR 0.41, 95% CI 0.19-0.88, P = 0.02). Mean fluoroscopy time was reduced in RMN group (-22.22 min; 95% CI -42.48 to -1.96, P = 0.03), although the overall duration of the procedure was longer (60.91 min; 95% CI 31.17 to 90.65, P < 0.0001). In conclusion, RMN is not superior to MCN in achieving freedom from recurrent AF at mid-term follow-up or PVI. The procedure implies less peri-procedural complications, requires a shorter fluoroscopy time but a longer total procedural time. For the low quality of the available evidence, a proper designed randomized controlled trial could turn the direction and the effect of the dimensions explored.

  10. 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

  11. Plasma microRNAs are associated with atrial fibrillation and change after catheter-ablation (the miRhythm Study)

    PubMed Central

    McManus, David D.; Tanriverdi, Kahraman; Lin, Honghuang; Esa, Nada; Kinno, Menhel; Mandapati, Divakar; Tam, Stanley; Okike, Okike N.; Ellinor, Patrick T.; Keaney, John F.; Donahue, J, Kevin; Benjamin, Emelia J.; Freedman, Jane E.

    2014-01-01

    Background MicroRNAs (miRNAs) are associated with cardiovascular disease (CVD), control gene expression, and are detectable in the circulation. Objective To test the hypothesis that circulating miRNAs would be associated with atrial fibrillation (AF). Methods Using a prospective study design powered to detect subtle differences in miRNAs, we quantified plasma expression of 86 miRNAs by high-throughput quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in 112 participants with AF and 99 without AF. To examine parallels between cardiac and plasma miRNA profiles, we quantified atrial tissue and plasma miRNA expression using qRT-PCR in 31 participants undergoing surgery. We also explored the hypothesis that lower AF burden after ablation would be reflected in the circulating blood pool by examining change in plasma miRNAs after AF ablation (n=47). Results The mean age of the cohort was 59 years. 58% of participants were men. Plasma miRs-21 and 150 were 2-fold lower in participants with AF than in those without AF after adjustment (p ≤ 0.0006). Plasma levels of miRs-21 and 150 were also lower in participants with paroxysmal AF than in those with persistent AF (p <0.05). Expression of miR-21, but not miR-150, was lower in atrial tissue from patients with AF compared to no AF (p<0.05). Plasma levels of miRs-21 and 150 increased 3-fold after AF ablation (p ≤ 0.0006). Conclusions Cardiac miRs-21 and 150 are known to regulate genes implicated in atrial remodeling. Our findings show associations between plasma miRs-21 and 150 and AF, suggesting that circulating miRNAs provide insights into cardiac gene regulation. PMID:25257092

  12. Comparison of Ablation Predictions for Carbonaceous Materials Using CEA and JANAF-Based Species Thermodynamics

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.

    2011-01-01

    In most previous work at NASA Ames Research Center, ablation predictions for carbonaceous materials were obtained using a species thermodynamics database developed by Aerotherm Corporation. This database is derived mostly from the JANAF thermochemical tables. However, the CEA thermodynamics database, also used by NASA, is considered more up to date. In this work, the FIAT code was modified to use CEA-based curve fits for species thermodynamics, then analyses using both the JANAF and CEA thermodynamics were performed for carbon and carbon phenolic materials over a range of test conditions. The ablation predictions are comparable at lower heat fluxes where the dominant mechanism is carbon oxidation. However, the predictions begin to diverge in the sublimation regime, with the CEA model predicting lower recession. The disagreement is more significant for carbon phenolic than for carbon, and this difference is attributed to hydrocarbon species that may contribute to the ablation rate.

  13. Can bedside patient-reported numbness predict postoperative ambulation ability for total knee arthroplasty patients with nerve block catheters?

    PubMed Central

    Mudumbai, Seshadri C.; Ganaway, Toni; Kim, T. Edward; Howard, Steven K.; Giori, Nicholas J.; Shum, Cynthia

    2016-01-01

    Background Adductor canal catheters offer advantages over femoral nerve catheters for knee replacement patients because they produce less quadriceps muscle weakness; however, applying adductor canal catheters in bedside clinical practice remains challenging. There is currently no patient-reported outcome that accurately predicts patients' physical function after knee replacement. The present study evaluates the validity of a relatively new patient-reported outcome, i.e., a numbness score obtained using a numeric rating scale, and assesses its predictive value on postoperative ambulation. Methods We conducted a retrospective cohort study pooling data from two previously-published clinical trials using identical research methodologies. Both studies recruited patients undergoing knee replacement; one studied adductor canal catheters while the other studied femoral nerve catheters. Our primary outcome was patient-reported numbness scores on postoperative day 1. We also examined postoperative day 1 ambulation distance and its association with postoperative numbness using linear regression, adjusting for age, body mass index, and physical status. Results Data from 94 subjects were included (femoral subjects, n = 46; adductor canal subjects, n = 48). Adductor canal patients reported decreased numbness (median [10th–90th percentiles]) compared to femoral patients (0 [0–5] vs. 4 [0–10], P = 0.001). Adductor canal patients also ambulated seven times further on postoperative day 1 relative to femoral patients. There was a significant association between postoperative day 1 total ambulation distance and numbness (Beta = –2.6; 95% CI: –4.5, –0.8, P = 0.01) with R2 = 0.1. Conclusions Adductor canal catheters facilitate improved early ambulation and produce less patient-reported numbness after knee replacement, but the correlation between these two variables is weak. PMID:26885299

  14. Novel P Wave Indices to Predict Atrial Fibrillation Recurrence After Radiofrequency Ablation for Paroxysmal Atrial Fibrillation

    PubMed Central

    Hu, Xiaoliang; Jiang, Jingzhou; Ma, Yuedong; Tang, Anli

    2016-01-01

    Background Circumferential pulmonary vein isolation (CPVI) is a widely used treatment for paroxysmal atrial fibrillation (AF). Several P wave duration (PWD) parameters have been suggested to predict post-ablation recurrence, but their use remains controversial. This study aimed to identify novel P wave indices that predict post-ablation AF recurrence. Material/Methods We selected 171 consecutive patients undergoing CPVI for paroxysmal AF. Electrocardiography (ECG) recordings were obtained at the beginning and the end of ablation. PWD was measured in all 12 leads. The PWD variation was calculated by subtracting the pre-ablation PWD from the post-ablation PWD. Results PWD was significantly shortened in leads II, III, aVF, and V1 after ablation. During a mean follow-up of 19.96±4.32 months, AF recurrence occurred in 32 (18.7%) patients. No significant differences in baseline characteristics or pre- or post-ablation PWD were observed between the AF recurrence and non-recurrence groups. Patients with AF recurrence exhibited a smaller PWD variation in leads II (1.21(−0.56, 2.40) vs. −5.77(−9.10, −4.06) ms, P<0.001), III (−5.92(−9.87, 3.27) vs. −9.44(−11.89, −5.57) ms, P=0.001) and V1 (−4.43(−6.64, −3.13) vs. −6.33(−8.19,−4.59) ms, P=0.003). Multivariable logistic regression analysis demonstrated that smaller PWD variations in lead II and III were independent risk factors for AF recurrence. PWD variation ≥−2.21 ms in lead II displayed the highest combined sensitivity and specificity (85.29% and 83.94%, respectively) for predicting post-ablation AF recurrence. A PWD variation ≥0 ms displayed the best practical value in predicting AF recurrence. Conclusions PWD variation in lead II is an effective predictor of post-ablation AF recurrence. PMID:27450644

  15. Endometrial ablation

    MedlinePlus

    Hysteroscopy-endometrial ablation; Laser thermal ablation; Endometrial ablation-radiofrequency; Endometrial ablation-thermal balloon ablation; Rollerball ablation; Hydrothermal ablation; Novasure ablation

  16. Pulmonary vein isolation using new technologies to improve ablation lesion formation: Initial results comparing enhanced catheter tip irrigation (Surround Flow®) with contact force measurement (Smarttouch®)

    PubMed Central

    Fichtner, Stephanie; Reents, Tilko; Ammar, Sonia; Semmler, Verena; Kathan, Susanne; Dillier, Roger; Buiatti, Alexandra; Hessling, Gabriele; Deisenhofer, Isabel

    2015-01-01

    Introduction Pulmonary vein reconnection after pulmonary vein isolation (PVI) is a significant problem in the treatment of paroxysmal atrial fibrillation (AF). We report about patients who underwent contact force (CF) guided PVI using CF catheter and compared them to patients with PVI using an ablation catheter with enhanced tip irrigation. Methods A total of 59 patients were included in the analysis. In 30 patients circumferential PVI was performed using the Thermocool Smarttouch® ablation catheter (ST) whereas in 29 patients circumferential PVI using the Thermocool Surround Flow SF® ablation catheter (SF) was performed. Patients were compared in regard to procedure time, fluoroscopy time/dose as well as RF-application duration and completeness of PVI. Adverse events (pericardial effusion, PV stenosis, stroke, death) were evaluated. The presence of sinus rhythm off antiarrhythmic medication was assessed during 6 months follow-up using multiple 7 day Holter-ECGs. Results In both groups, all PVs were isolated without serious adverse events. Procedure time was 2.15 ± 0.5 h (ST) vs. 2.37 ± 1.13 h (SF) (p = 0.19). Duration of RF-applications was 46.6 ± 18 min (ST) and 49.8 ± 19 min (SF) (p = 0.52). Fluoroscopy time was 25.2 ± 13 min (ST) vs. 29 ± 18 min (SF), fluoroscopy dose 2675.6 ± 1658 versus 3038.3 ± 1997 cGym2 (p = 0.36 and 0.46 respectively). Sinus rhythm off antiarrhythmic medication validated with 7 day Holter ECGs was present in both groups in 72% of patients after 6 months of follow up. Conclusion PVI using the new contact force catheter is safe and effective in patients with paroxysmal AF. PMID:26937108

  17. A theoretical model to predict tensile deformation behavior of balloon catheter.

    PubMed

    Todo, Mitsugu; Yoshiya, Keiji; Matsumoto, Takuya

    2016-09-01

    In this technical note, a simple theoretical model was proposed to express the tensile deformation and fracture of balloon catheter tested by the ISO standard using piece-wise linear force-displacement relations. The model was then validated by comparing with the tensile force-displacement behaviors of two types of typical balloon catheters clinically used worldwide. It was shown that the proposed model can effectively be used to express the tensile deformation behavior and easily be handled by physicians who are not familiar with mechanics of materials. PMID:27214691

  18. Prediction of Ablation Rates from Solid Surfaces Exposed to High Temperature Gas Flow

    NASA Technical Reports Server (NTRS)

    Akyuzlu, Kazim M.; Coote, David

    2013-01-01

    ablation. Two different ablation models are proposed to determine the heat loss from the solid surface due to the ablation of the solid material. Both of them are physics based. Various numerical simulations were carried out using both models to predict the temperature distribution in the solid and in the gas flow, and then predict the ablation rates at a typical NTR motor hydrogen gas temperature and pressure. Solid mass loss rate per foot of a pipe was also calculated from these predictions. The results are presented for fully developed turbulent flow conditions in a sample SS pipe with a 6 inch diameter.

  19. FACTOR VIII MAY PREDICT CATHETER-RELATED THROMBOSIS IN CRITICALLY ILL CHILDREN: A PRELIMINARY STUDY

    PubMed Central

    Faustino, Edward Vincent S.; Li, Simon; Silva, Cicero T.; Pinto, Matthew G.; Qin, Li; Tala, Joana A.; Rinder, Henry M.; Kupfer, Gary M.; Shapiro, Eugene D.

    2015-01-01

    OBJECTIVE If we can identify critically ill children at high risk for central venous catheter-related thrombosis, then we could target them for pharmacologic thromboprophylaxis. We determined whether factor VIII activity or G value was associated with catheter-related thrombosis in critically ill children. DESIGN Prospective cohort study SETTING Two tertiary academic centers PATIENTS We enrolled children <18 years old who were admitted to the pediatric intensive care unit within 24 hours after insertion of a central venous catheter. We excluded children with a recently diagnosed thrombotic event or those anticipated to receive anticoagulation. Children with thrombosis diagnosed with surveillance ultrasonography on the day of enrollment were classified as having prevalent thrombosis. Those who developed catheter-related thrombosis thereafter were classified as having incident thrombosis. INTERVENTIONS None MEASUREMENTS AND MAIN RESULTS We enrolled 85 children in the study. Once enrolled, we measured factor VIII activity with one-stage clotting assay and determined G value with thromboelastography. Of those enrolled, 25 had incident and 12 had prevalent thromboses. The odds ratio for incident thrombosis per standard deviation increase in factor VIII activity was 1.98 (95% confidence interval: 1.10-3.55). The area under the receiver operating characteristic curve was 0.66 (95% confidence interval: 0.52-0.79). At factor VIII activity >100 IU/dL, which was the optimal threshold identified using Youden index, sensitivity and specificity were 92.0% and 41.3%, respectively. The association between factor VIII activity and incident thrombosis remained significant after adjusting for important clinical predictors of thrombosis (odds ratio: 1.93; 95% confidence interval: 1.10-3.39). G value was associated with prevalent but not with incident thrombosis. CONCLUSION Factor VIII activity may be used to stratify critically ill children based on their risk for catheter

  20. Optothermal profile of an ablation catheter with integrated microcoil for MR-thermometry during Nd:YAG laser interstitial thermal therapies of the liver—An in-vitro experimental and theoretical study

    PubMed Central

    Kardoulaki, Evdokia M.; Syms, Richard R. A.; Young, Ian R.; Choonee, Kaushal; Rea, Marc; Gedroyc, Wladyslaw M. W.

    2015-01-01

    Purpose: Flexible microcoils integrated with ablation catheters can improve the temperature accuracy during local MR-thermometry in Nd:YAG laser interstitial thermal therapies. Here, the authors are concerned with obtaining a preliminary confirmation of the clinical utility of the modified catheter. They investigate whether the thin-film substrate and copper tracks of the printed coil inductor affect the symmetry of the thermal profile, and hence of the lesion produced. Methods: Transmission spectroscopy in the near infrared was performed to test for the attenuation at 1064 nm through the 25 μm thick Kapton substrate of the microcoil. The radial transmission profile of an infrared high-power, light emitting diode with >80% normalized power at 1064 nm was measured through a cross section of the modified applicator to assess the impact of the copper inductor on the optical profile. The measurements were performed in air, as well as with the applicator surrounded by two types of scattering media; crystals of NaCl and a layer of liver-mimicking gel phantom. A numerical model based on Huygens–Fresnel principle and finite element simulations, using a commercially available package (COMSOL Multiphysics), were employed to compare with the optical measurements. The impact of the modified optical profile on the thermal symmetry was assessed by examining the high resolution microcoil derived thermal maps from a Nd:YAG laser ablation performed on a liver-mimicking gel phantom. Results: Less than 30% attenuation through the Kapton film was verified. Shadowing behind the copper tracks was observed in air and the measured radial irradiation correlated well with the diffraction pattern calculated numerically using the Huygens–Fresnel principle. Both optical experiments and simulations, demonstrate that shadowing is mitigated by the scattering properties of a turbid medium. The microcoil derived thermal maps at the end of a Nd:YAG laser ablation performed on a gel phantom in a

  1. Catheter Ablation of Ventricular Tachycardia

    MedlinePlus

    ... like to see the Circulation web site. Your Personal Message Send Message ... Scholar Cited By... Cardiac tachyarrhythmias and patient values and preferences for their management: the European Heart ...

  2. A novel parameter for predicting arterial fusion and ablation in finite element models

    NASA Astrophysics Data System (ADS)

    Fankell, Douglas; Kramer, Eric; Taylor, Kenneth; Ferguson, Virginia; Rentschler, Mark E.

    2015-03-01

    Tissue fusion devices apply heat and pressure to ligate or ablate blood vessels during surgery. Although this process is widely used, a predictive finite element (FE) model incorporating both structural mechanics and heat transfer has not been developed, limiting improvements to empirical evidence. This work presents the development of a novel damage parameter, which incorporates stress, water content and temperature, and demonstrates its application in a FE model. A FE model, using the Holzapfel-Gasser-Ogden strain energy function to represent the structural mechanics and equations developed by Cezo to model water content and heat transfer, was created to simulate the fusion or ablation of a porcine splenic artery. Using state variables, the stresses, temperature and water content are recorded and combined to create a single parameter at each integration point. The parameter is then compared to a critical value (determined through experiments). If the critical value is reached, the element loses all strength. If the value is not reached, no change occurs. Little experimental data exists for validation, but the resulting stresses, temperatures and water content fall within ranges predicted by prior work. Due to the lack of published data, additional experimental studies are being conducted to rigorously validate and accurately determine the critical value. Ultimately, a novel method for demonstrating tissue damage and fusion in a FE model is presented, providing the first step towards in-depth FE models simulating fusion and ablation of arteries.

  3. Intra-atrial conduction block mimicking atrioventricular nodal block after multiple catheter ablation procedures for atrial tachycardia in a patient with cardiomyopathy.

    PubMed

    Chugh, Aman; Yokokawa, Miki; Baman, Timir; Bogun, Frank; Wu, Audrey

    2012-11-01

    A 42-year-old woman with a history of cardiomyopathy and multiple ablation procedures for atrial tachycardia developed intra-atrial conduction block that mimicked atrioventricular (AV) nodal block during radiofrequency ablation at the cavotricuspid isthmus. She was treated with atrial pacing (from the coronary sinus), which overcame intra-atrial conduction block and resulted in AV nodal conduction.

  4. Larger low voltage zone in endocardial unipolar map compared with that in epicardial bipolar map indicates difficulty in eliminating ventricular tachycardia by catheter ablation.

    PubMed

    Miyamoto, Koji; Noda, Takashi; Satomi, Kazuhiro; Wada, Mitsuru; Nakajima, Ikutaro; Ishibashi, Kohei; Okamura, Hideo; Noguchi, Teruo; Anzai, Toshihisa; Yasuda, Satoshi; Ogawa, Hisao; Shimizu, Wataru; Aiba, Takeshi; Kamakura, Shiro; Kusano, Kengo

    2016-08-01

    Patients with ischemic and non-ischemic cardiomyopathy often have substrate for ventricular tachycardia (VT) in the endocardium (ENDO), epicardium (EPI), and/or intramural. Although it has been reported that the ENDO unipolar (UNI) voltage map is useful in detecting EPI substrate, its feasibility to detect intramural scarring and its usefulness in radiofrequency catheter ablation (RFCA) remain unclear. To assess the relationship between the left ventricle (LV) ENDO UNI voltage map and the LV EPI bipolar (BIP) voltage map, and to determine the usefulness of the ENDO UNI voltage map to guide RFCA for VT in patients with cardiomyopathy undergoing combined ENDO- and EPI RFCA. Eleven patients with VT undergoing detailed ENDO and EPI electroanatomical mapping of the LV were included (mean age 59 ± 11 years, 9 men). We assessed the value of the LV ENDO UNI voltage map in identifying EPI and/or intramural substrate in these 11 patients with non-ischemic or ischemic cardiomyopathy. The underlying heart disease was dilated cardiomyopathy in 4 patients, cardiac sarcoidosis in 3, hypertrophic cardiomyopathy in 2, and ischemic heart disease in 2 patients. The mean LV ejection fraction was 24 ± 7 %. The low voltage zone (LVZ) was defined as <1.5 mV for LV ENDO BIP electrograms (EGMs), <8.3 mV for LV ENDO UNI EGMs, and <1.0 mV for LV EPI BIP EGMs. The surface area of each LVZ was measured. We also measured the LVZ of the spatial overlap between ENDO UNI and EPI BIP voltage maps using the transparency mode on CARTO software. We performed RFCA at the ENDO and EPI based on activation and/or substrate maps, targeting the LVZ and/or abnormal EGMs. The LVZ was present in the LV ENDO BIP voltage map in 10 of 11 patients (42 ± 33 cm(2)), and in the LV ENDO UNI voltage map in 10 of 11 patients (72 ± 45 cm(2)). The LVZ was present in the EPI BIP voltage map in 9 of 11 patients (70 ± 61 cm(2)), and the LVZ in the ENDO UNI voltage map was also seen in all 9 patients

  5. Larger low voltage zone in endocardial unipolar map compared with that in epicardial bipolar map indicates difficulty in eliminating ventricular tachycardia by catheter ablation.

    PubMed

    Miyamoto, Koji; Noda, Takashi; Satomi, Kazuhiro; Wada, Mitsuru; Nakajima, Ikutaro; Ishibashi, Kohei; Okamura, Hideo; Noguchi, Teruo; Anzai, Toshihisa; Yasuda, Satoshi; Ogawa, Hisao; Shimizu, Wataru; Aiba, Takeshi; Kamakura, Shiro; Kusano, Kengo

    2016-08-01

    Patients with ischemic and non-ischemic cardiomyopathy often have substrate for ventricular tachycardia (VT) in the endocardium (ENDO), epicardium (EPI), and/or intramural. Although it has been reported that the ENDO unipolar (UNI) voltage map is useful in detecting EPI substrate, its feasibility to detect intramural scarring and its usefulness in radiofrequency catheter ablation (RFCA) remain unclear. To assess the relationship between the left ventricle (LV) ENDO UNI voltage map and the LV EPI bipolar (BIP) voltage map, and to determine the usefulness of the ENDO UNI voltage map to guide RFCA for VT in patients with cardiomyopathy undergoing combined ENDO- and EPI RFCA. Eleven patients with VT undergoing detailed ENDO and EPI electroanatomical mapping of the LV were included (mean age 59 ± 11 years, 9 men). We assessed the value of the LV ENDO UNI voltage map in identifying EPI and/or intramural substrate in these 11 patients with non-ischemic or ischemic cardiomyopathy. The underlying heart disease was dilated cardiomyopathy in 4 patients, cardiac sarcoidosis in 3, hypertrophic cardiomyopathy in 2, and ischemic heart disease in 2 patients. The mean LV ejection fraction was 24 ± 7 %. The low voltage zone (LVZ) was defined as <1.5 mV for LV ENDO BIP electrograms (EGMs), <8.3 mV for LV ENDO UNI EGMs, and <1.0 mV for LV EPI BIP EGMs. The surface area of each LVZ was measured. We also measured the LVZ of the spatial overlap between ENDO UNI and EPI BIP voltage maps using the transparency mode on CARTO software. We performed RFCA at the ENDO and EPI based on activation and/or substrate maps, targeting the LVZ and/or abnormal EGMs. The LVZ was present in the LV ENDO BIP voltage map in 10 of 11 patients (42 ± 33 cm(2)), and in the LV ENDO UNI voltage map in 10 of 11 patients (72 ± 45 cm(2)). The LVZ was present in the EPI BIP voltage map in 9 of 11 patients (70 ± 61 cm(2)), and the LVZ in the ENDO UNI voltage map was also seen in all 9 patients

  6. Prediction of early-onset atrial tachyarrhythmia after successful trans-catheter device closure of atrial septal defect

    PubMed Central

    Park, Kyoung-Min; Hwang, Jin Kyung; Chun, Kwang Jin; Park, Seung-Jung; On, Young Keun; Kim, June Soo; Park, Seung Woo; Kang, I-Seok; Song, Jinyoung; Huh, June

    2016-01-01

    Abstract Atrial tachyarrhythmia is a well-known long-term complication of atrial septal defect (ASD) in adults, even after successful trans-catheter closure. However, the risk factors for early-onset atrial tachyarrhythmia after trans-catheter closure remain unclear. This retrospective study enrolled adults with secundum ASD undergoing trans-catheter closure from January 2000 to March 2014. We analyzed the clinical characteristics of patients and assessed risk factors for new-onset atrial tachyarrhythmia defined as a composite of atrial fibrillation or flutter (AF/AFL) after ASD closure. We enrolled a total of 427 patients; 123 were male (28.8%) and the median age was 37.0 (interquartile range [IQR]: 18.3–49.0). Nineteen (4.4%) patients had documented atrial tachyarrhythmia during the follow-up period (median: 11.4 months [IQR: 5.4–24]). Patients with transient AF/AFL during closure showed a greater incidence of new-onset atrial tachyarrhythmia during the follow-up period than patients with consistent sinus rhythm during closure (27.3% vs 3.8%; P = 0.01). Most new-onset atrial tachyarrhythmias were documented within 6 months (median: 2.6 [IQR: 1.2–4.1] months) of closure. In the multivariate analysis, the risk for new-onset atrial tachyarrhythmia was significant in patients with AF/AFL during closure (hazard ratio [HR]: 9.90, 95% confidence interval [CI]: 2.86–34.20; P < 0.001), deficient posteroinferior rim (HR: 5.48, 95% CI: 1.15–25.72; P = 0.04), and age of closure over 48 years (HR: 3.30, 95% CI: 1.30–8.38; P = 0.01). In conclusion, transient AF/AFL during trans-catheter closure of ASD as well as deficient posteroinferior rim and age of closure over 48 years may be useful for predicting early new-onset atrial tachyarrhythmia after device closure. PMID:27583905

  7. Prediction of early-onset atrial tachyarrhythmia after successful trans-catheter device closure of atrial septal defect.

    PubMed

    Park, Kyoung-Min; Hwang, Jin Kyung; Chun, Kwang Jin; Park, Seung-Jung; On, Young Keun; Kim, June Soo; Park, Seung Woo; Kang, I-Seok; Song, Jinyoung; Huh, June

    2016-08-01

    Atrial tachyarrhythmia is a well-known long-term complication of atrial septal defect (ASD) in adults, even after successful trans-catheter closure. However, the risk factors for early-onset atrial tachyarrhythmia after trans-catheter closure remain unclear. This retrospective study enrolled adults with secundum ASD undergoing trans-catheter closure from January 2000 to March 2014. We analyzed the clinical characteristics of patients and assessed risk factors for new-onset atrial tachyarrhythmia defined as a composite of atrial fibrillation or flutter (AF/AFL) after ASD closure. We enrolled a total of 427 patients; 123 were male (28.8%) and the median age was 37.0 (interquartile range [IQR]: 18.3-49.0). Nineteen (4.4%) patients had documented atrial tachyarrhythmia during the follow-up period (median: 11.4 months [IQR: 5.4-24]). Patients with transient AF/AFL during closure showed a greater incidence of new-onset atrial tachyarrhythmia during the follow-up period than patients with consistent sinus rhythm during closure (27.3% vs 3.8%; P = 0.01). Most new-onset atrial tachyarrhythmias were documented within 6 months (median: 2.6 [IQR: 1.2-4.1] months) of closure. In the multivariate analysis, the risk for new-onset atrial tachyarrhythmia was significant in patients with AF/AFL during closure (hazard ratio [HR]: 9.90, 95% confidence interval [CI]: 2.86-34.20; P < 0.001), deficient posteroinferior rim (HR: 5.48, 95% CI: 1.15-25.72; P = 0.04), and age of closure over 48 years (HR: 3.30, 95% CI: 1.30-8.38; P = 0.01). In conclusion, transient AF/AFL during trans-catheter closure of ASD as well as deficient posteroinferior rim and age of closure over 48 years may be useful for predicting early new-onset atrial tachyarrhythmia after device closure. PMID:27583905

  8. Serum Galectin-3 Levels Predict Recurrences after Ablation of Atrial Fibrillation

    PubMed Central

    Clementy, Nicolas; Benhenda, Nazih; Piver, Eric; Pierre, Bertrand; Bernard, Anne; Fauchier, Laurent; Pages, Jean-Christophe; Babuty, Dominique

    2016-01-01

    Galectin-3 is a biomarker of fibrosis and atrial remodeling, involved in the mechanisms of initiation and maintenance of atrial fibrillation (AF). We sought to study the accuracy of galectin-3 level in predicting recurrences of AF after ablation. Serum concentrations of galectin-3 were determined in a consecutive series of patients addressed for AF ablation in our center. After a 3-month blanking period, recurrences of atrial arrhythmias were collected during the first year in all patients, using Holter monitoring at 3, 6 months and 12 months. A total of 160 patients were included, with a mean galectin-3 rate was 14.4 ± 5.6 ng/mL. At 12-month, 55 patients (34%) had reexperienced sustained atrial arrhythmia. Only higher galectin-3 level (HR = 1.07 [1.01–1.12], p = 0.02) and larger left atrial diameter (HR = 1.07 [1.03–1.12], p = 0.001) independently predicted recurrence. Patients with both galectin-3 level <15 ng/mL and left atrial diameter <40 millimeters had a 1-year arrhythmia-free survival rate − after a single procedure without anti-arrhythmic drug − of 91%, as compared with 41% in patients with galectin-3 ≥ 15 and left trial diameter ≥40 (p < 0.0001), whether AF was paroxysmal or persistent. Galectin-3 and left atrial diameters, rather than clinical presentation of AF, predict recurrences after ablation. PMID:27677964

  9. Predictable surface ablation of dielectrics with few-cycle laser pulse even beyond air ionization

    NASA Astrophysics Data System (ADS)

    Pasquier, C.; Sentis, M.; Utéza, O.; Sanner, N.

    2016-08-01

    We study surface ablation of dielectrics with single-shot few-cycle optical pulse (˜10 fs) in air, at intensities below and above the onset of air ionization. We perform 3D analysis and careful calibration of the fluence distribution at the laser focus, spanning from linear- to nonlinear- focusing regimes, enabling to thoroughly characterize the severe limitation of the fluence delivered onto the sample surface upon increase of incident pulse energy. Despite significant beam reshaping taking place at high fluence, we demonstrate that it is nevertheless possible to confidently predict the resulting crater profiles on fused silica surface, even in the regime of filamentation.

  10. Macro-reentrant atrial tachycardia conducting through a left superior vena cava after catheter ablation in a patient with paroxysmal atrial fibrillation.

    PubMed

    Kurotobi, Toshiya; Kino, Naoto; Tonomura, Daisuke; Shimada, Yoshihisa

    2015-01-01

    A left superior vena cava can be a cause of cardiac rhythm or conduction abnormalities, and can also be the arrhythmogenic source of atrial fibrillation (AF) with connections to the coronary sinus and left atrium. In the present study, we report a case with a macro re-entrant atrial tachycardia that coursed through the left superior vena cava after a previous AF ablation, which successfully ablated paroxysmal AF.

  11. Periprocedural 3D imaging of the left atrium and esophagus: comparison of different protocols of 3D rotational angiography of the left atrium and esophagus in group of 547 consecutive patients undergoing catheter ablation of the complex atrial arrhythmias.

    PubMed

    Starek, Zdenek; Lehar, František; Jez, Jiri; Wolf, Jiri; Kulik, Tomas; Zbankova, Alena; Novak, Miroslav

    2016-07-01

    A new method in creating 3D models of the left atrium (LA) and esophagus before catheter ablation of atrial arrhythmias is 3D rotational angiography (3DRA) of the LA. The purpose of this retrospective study was to test various acquisition protocols of the 3DRA and attempt to define the parameters influencing the success of the protocols. From August 2010 to November 2014, 3DRA of the LA using the Philips Allura FD 10 X-ray system was performed in 547 consecutive patients using right atrial and left atrial protocols. Visualization of the esophagus was performed after oral administration of a contrast agent. Patients were monitored for success (creation of a useful 3D models) and evaluated for a number of parameters affecting the success of 3DRA. The success of the RA protocol was 88.89 % with and 91.91 % without esophagus imaging. The success of the LA protocol was 97.42 % with and 94.54 % without esophagus imaging. The only factor reducing the success of the RA protocol was BMI; the LA protocol was not influenced by any factor. Ventricular fibrillation induced in two patients was successfully treated with defibrillation. 3DRA of the LA is a reliable method that supports catheter ablation of complex atrial arrhythmias. The LA protocol with esophagus imaging was significantly more reliable than the RA protocol; the other protocols were comparable. The RA protocol may be negatively affected by high BMI. Simultaneous imaging of the esophagus is safe and feasible, and the LA protocol can be recommended.

  12. Periprocedural 3D imaging of the left atrium and esophagus: comparison of different protocols of 3D rotational angiography of the left atrium and esophagus in group of 547 consecutive patients undergoing catheter ablation of the complex atrial arrhythmias.

    PubMed

    Starek, Zdenek; Lehar, František; Jez, Jiri; Wolf, Jiri; Kulik, Tomas; Zbankova, Alena; Novak, Miroslav

    2016-07-01

    A new method in creating 3D models of the left atrium (LA) and esophagus before catheter ablation of atrial arrhythmias is 3D rotational angiography (3DRA) of the LA. The purpose of this retrospective study was to test various acquisition protocols of the 3DRA and attempt to define the parameters influencing the success of the protocols. From August 2010 to November 2014, 3DRA of the LA using the Philips Allura FD 10 X-ray system was performed in 547 consecutive patients using right atrial and left atrial protocols. Visualization of the esophagus was performed after oral administration of a contrast agent. Patients were monitored for success (creation of a useful 3D models) and evaluated for a number of parameters affecting the success of 3DRA. The success of the RA protocol was 88.89 % with and 91.91 % without esophagus imaging. The success of the LA protocol was 97.42 % with and 94.54 % without esophagus imaging. The only factor reducing the success of the RA protocol was BMI; the LA protocol was not influenced by any factor. Ventricular fibrillation induced in two patients was successfully treated with defibrillation. 3DRA of the LA is a reliable method that supports catheter ablation of complex atrial arrhythmias. The LA protocol with esophagus imaging was significantly more reliable than the RA protocol; the other protocols were comparable. The RA protocol may be negatively affected by high BMI. Simultaneous imaging of the esophagus is safe and feasible, and the LA protocol can be recommended. PMID:27116237

  13. Repeat Catheter Ablation of Long-standing Persistent Atrial Fibrillation in Patients with a Total Atrial Fibrillation Duration of More Than 2 Years: Effects of the CHA2DS2-VASc Score and Estimated Glomerular Filtration Rate on the Outcomes.

    PubMed

    Wang, Qian; Jiang, Shi-Li; Liu, Xu; Yang, Yi-Qing

    2016-01-01

    Objective Little is known about the outcome of repeat catheter ablation of long-standing persistent atrial fibrillation (AF) in patients with a total AF duration of more than 2 years. The main objective of this study was to explore the results and factors affecting the clinical success rate of these repeat procedures. Methods We enrolled 99 patients with a total AF duration of more than 2 years and recurrent atrial arrhythmias after the initial catheter ablation of long-standing persistent AF. The enrolled patients were divided into two groups named the AF-recurrence group (50 patients) and the atrial tachycardia (AT)-recurrence group (49 patients) and all underwent a strict follow-up. The quality of life (QOL) and AF-related symptom classification were assessed at baseline and at 24 months post re-ablation. Results After a mean follow-up of 31 months, 30 (30.3%) patients were free from arrhythmia recurrence, and the success rate in the AT-recurrence group was higher than that in the AF-recurrence group (32.7% vs. 28.0%, p=0.614). A Cox regression analysis revealed a CHA2DS2-VASc score ≥3 to be a predictor of recurrence. AF recurrent patients with an abnormal renal function were more prone to undergo a failed procedure. However, an abnormal renal function had no effect on the outcome of the repeat procedure for patients with AT recurrence. At the 24-month follow-up, patients maintaining sinus rhythm (SR) had a significantly improved QOL and AF-related symptoms. Conclusion The success rate of repeat procedures for long-standing persistent AF and a total AF duration of more than 2 years is poor for patients with a CHA2DS2-VASc score ≥3. An impaired renal function has an unfavorable effect on the outcome for patients with AF recurrence. For patients maintaining SR, both the QOL and AF symptomatology improve significantly. PMID:27629945

  14. Viscous code prediction of re-entry vehicle roll torque based on ablated surface topology

    NASA Astrophysics Data System (ADS)

    Szostowski, D. J.; Lowe, D. L.; Nestler, D. E.

    1982-06-01

    A new approach is developed for modeling roll torque due to ablated surface features of tape-wrapped, carbon-phenolic heatshields. The approach stems from preferential and random asymmetric topological characteristics observed on material specimens from ground test models and recovered re-entry vehicles. Roll torque contributions from each type of surface feature are determined from aerodynamic models coupled to an integral viscous technique. The dominant roll-producing mechanisms are shown to be warp yarn bias surface roughness and the formation of asymmetric char ledges. Comparisons with flight test roll histories validate the framework for the roll modeling technique, including predictions for a class of vehicle differing substantially from the one for which the model was developed.

  15. Urinary catheter - infants

    MedlinePlus

    Bladder catheter - infants; Foley catheter - infants; Urinary catheter - neonatal ... A urinary catheter is a small, soft tube placed in the bladder. This article addresses urinary catheters in babies. WHY IS ...

  16. Planning Irreversible Electroporation in the Porcine Kidney: Are Numerical Simulations Reliable for Predicting Empiric Ablation Outcomes?

    SciTech Connect

    Wimmer, Thomas Srimathveeravalli, Govindarajan; Gutta, Narendra; Ezell, Paula C.; Monette, Sebastien; Maybody, Majid; Erinjery, Joseph P.; Durack, Jeremy C.; Coleman, Jonathan A.; Solomon, Stephen B.

    2015-02-15

    PurposeNumerical simulations are used for treatment planning in clinical applications of irreversible electroporation (IRE) to determine ablation size and shape. To assess the reliability of simulations for treatment planning, we compared simulation results with empiric outcomes of renal IRE using computed tomography (CT) and histology in an animal model.MethodsThe ablation size and shape for six different IRE parameter sets (70–90 pulses, 2,000–2,700 V, 70–100 µs) for monopolar and bipolar electrodes was simulated using a numerical model. Employing these treatment parameters, 35 CT-guided IRE ablations were created in both kidneys of six pigs and followed up with CT immediately and after 24 h. Histopathology was analyzed from postablation day 1.ResultsAblation zones on CT measured 81 ± 18 % (day 0, p ≤ 0.05) and 115 ± 18 % (day 1, p ≤ 0.09) of the simulated size for monopolar electrodes, and 190 ± 33 % (day 0, p ≤ 0.001) and 234 ± 12 % (day 1, p ≤ 0.0001) for bipolar electrodes. Histopathology indicated smaller ablation zones than simulated (71 ± 41 %, p ≤ 0.047) and measured on CT (47 ± 16 %, p ≤ 0.005) with complete ablation of kidney parenchyma within the central zone and incomplete ablation in the periphery.ConclusionBoth numerical simulations for planning renal IRE and CT measurements may overestimate the size of ablation compared to histology, and ablation effects may be incomplete in the periphery.

  17. Noninvasive Fibrosis Marker Can Predict Recurrence of Hepatocellular Carcinoma after Radiofrequency Ablation

    PubMed Central

    Chung, Hyun Ah; Kim, Jeong-Han; Hwang, Young; Choi, Hong Seok; Ko, Soon Young; Choe, Won Hyeok; Kwon, So Young

    2016-01-01

    Background/Aims: Tumor recurrence after curative therapy is common for patients with hepatocellular carcinoma (HCC). As fibrosis and chronic inflammation contribute to the progression of HCC, we aimed to identify the predictive value of inflammatory and fibrosis markers for HCC recurrence after curative therapy using radiofrequency ablation (RFA). Materials and Methods: We retrospectively reviewed the records of patients with HCC treated with RFA between October 2005 and September 2013. The median duration of follow-up was 40 months (4–95 months). Inflammatory and fibrosis markers and demographic and clinical data were analyzed by Cox proportional hazards model using univariate and multivariate analyses and longitudinal analysis. Results: A total of 98 patients were included for analysis. There were 54 cases of HCC recurrence (55.1%). The aspartate aminotransferase-to-platelet ratio index (APRI; 2.3 ± 1.8 vs. 1.3 ± 1.4, P = 0.018) was significantly higher in the recurrence group than in the recurrence-free group. In multivariate analysis, APRI (hazard ratio, 2.64; confidence interval, 1.488–4.714; P = 0.001) was an independent risk factor for tumor recurrence. In particular, patients with APRI >1.38 showed a higher recurrence rate than patients with APRI ≤1.38 (P < 0.001). Longitudinal analysis showed persistently higher APRI values when assessed 12 months after RFA in patients who developed recurrence during follow-up than those who remained recurrence-free. Conclusions: These findings show that a high APRI value is associated with HCC recurrence after RFA. Therefore, APRI could play an important role in predicting HCC recurrence after RFA. PMID:26831608

  18. Post-procedural evaluation of catheter contact force characteristics

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    Minimally invasive catheter ablation of electric foci, performed in electrophysiology labs, is an attractive treatment option for atrial fibrillation (AF) - in particular if drug therapy is no longer effective or tolerated. There are different strategies to eliminate the electric foci inducing the arrhythmia. Independent of the particular strategy, it is essential to place transmural lesions. The impact of catheter contact force on the generated lesion quality has been investigated recently, and first results are promising. There are different approaches to measure catheter-tissue contact. Besides traditional haptic feedback, there are new technologies either relying on catheter tip-to-tissue contact force or on local impedance measurements at the tip of the catheter. In this paper, we present a novel tool for post-procedural ablation point evaluation and visualization of contact force characteristics. Our method is based on localizing ablation points set during AF ablation procedures. The 3-D point positions are stored together with lesion specific catheter contact force (CF) values recorded during the ablation. The force records are mapped to the spatial 3-D positions, where the energy has been applied. The tracked positions of the ablation points can be further used to generate a 3-D mesh model of the left atrium (LA). Since our approach facilitates visualization of different force characteristics for post-procedural evaluation and verification, it has the potential to improve outcome by highlighting areas where lesion quality may be less than desired.

  19. Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation

    PubMed Central

    Kosmidou, Ioanna; Wooden, Shannnon; Jones, Brian; Deering, Thomas; Wickliffe, Andrew; Dan, Dan

    2013-01-01

    Cryoballoon ablation (CBA) is an established therapy for atrial fibrillation (AF). Pulmonary vein (PV) occlusion is essential for achieving antral contact and PV isolation and is typically assessed by contrast injection. We present a novel method of direct pressure monitoring for assessment of PV occlusion. Transcatheter pressure is monitored during balloon advancement to the PV antrum. Pressure is recorded via a single pressure transducer connected to the inner lumen of the cryoballoon. Pressure curve characteristics are used to assess occlusion in conjunction with fluoroscopic or intracardiac echocardiography (ICE) guidance. PV occlusion is confirmed when loss of typical left atrial (LA) pressure waveform is observed with recordings of PA pressure characteristics (no A wave and rapid V wave upstroke). Complete pulmonary vein occlusion as assessed with this technique has been confirmed with concurrent contrast utilization during the initial testing of the technique and has been shown to be highly accurate and readily reproducible. We evaluated the efficacy of this novel technique in 35 patients. A total of 128 veins were assessed for occlusion with the cryoballoon utilizing the pressure monitoring technique; occlusive pressure was demonstrated in 113 veins with resultant successful pulmonary vein isolation in 111 veins (98.2%). Occlusion was confirmed with subsequent contrast injection during the initial ten procedures, after which contrast utilization was rapidly reduced or eliminated given the highly accurate identification of occlusive pressure waveform with limited initial training. Verification of PV occlusive pressure during CBA is a novel approach to assessing effective PV occlusion and it accurately predicts electrical isolation. Utilization of this method results in significant decrease in fluoroscopy time and volume of contrast. PMID:23485956

  20. Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser.

    PubMed

    Kozub, John A; Shen, Jin-H; Joos, Karen M; Prasad, Ratna; Hutson, M Shane

    2015-10-01

    Previous research showed that mid-infrared free-electron lasers could reproducibly ablate soft tissue with little collateral damage. The potential for surgical applications motivated searches for alternative tabletop lasers providing thermally confined pulses in the 6- to-7-µm wavelength range with sufficient pulse energy, stability, and reliability. Here, we evaluate a prototype Raman-shifted alexandrite laser. We measure ablation thresholds, etch rates, and collateral damage in gelatin and cornea as a function of laser wavelength (6.09, 6.27, or 6.43 µm), pulse energy (up to 3 mJ/pulse), and spot diameter (100 to 600 µm). We find modest wavelength dependence for ablation thresholds and collateral damage, with the lowest thresholds and least damage for 6.09 µm. We find a strong spot-size dependence for all metrics. When the beam is tightly focused (~100-µm diameter), ablation requires more energy, is highly variable and less efficient, and can yield large zones of mechanical damage (for pulse energies>1 mJ). When the beam is softly focused (~300-µm diameter), ablation proceeded at surgically relevant etch rates, with reasonable reproducibility (5% to 12% within a single sample), and little collateral damage. With improvements in pulse-energy stability, this prototype laser may have significant potential for soft-tissue surgical applications.

  1. Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser

    PubMed Central

    Kozub, John A.; Shen, Jin-H.; Joos, Karen M.; Prasad, Ratna; Shane Hutson, M.

    2015-01-01

    Abstract. Previous research showed that mid-infrared free-electron lasers could reproducibly ablate soft tissue with little collateral damage. The potential for surgical applications motivated searches for alternative tabletop lasers providing thermally confined pulses in the 6- to-7-μm wavelength range with sufficient pulse energy, stability, and reliability. Here, we evaluate a prototype Raman-shifted alexandrite laser. We measure ablation thresholds, etch rates, and collateral damage in gelatin and cornea as a function of laser wavelength (6.09, 6.27, or 6.43  μm), pulse energy (up to 3  mJ/pulse), and spot diameter (100 to 600  μm). We find modest wavelength dependence for ablation thresholds and collateral damage, with the lowest thresholds and least damage for 6.09  μm. We find a strong spot-size dependence for all metrics. When the beam is tightly focused (∼100-μm diameter), ablation requires more energy, is highly variable and less efficient, and can yield large zones of mechanical damage (for pulse energies >1  mJ). When the beam is softly focused (∼300-μm diameter), ablation proceeded at surgically relevant etch rates, with reasonable reproducibility (5% to 12% within a single sample), and little collateral damage. With improvements in pulse-energy stability, this prototype laser may have significant potential for soft-tissue surgical applications. PMID:26456553

  2. Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser

    NASA Astrophysics Data System (ADS)

    Kozub, John A.; Shen, Jin-H.; Joos, Karen M.; Prasad, Ratna; Shane Hutson, M.

    2015-10-01

    Previous research showed that mid-infrared free-electron lasers could reproducibly ablate soft tissue with little collateral damage. The potential for surgical applications motivated searches for alternative tabletop lasers providing thermally confined pulses in the 6- to-7-μm wavelength range with sufficient pulse energy, stability, and reliability. Here, we evaluate a prototype Raman-shifted alexandrite laser. We measure ablation thresholds, etch rates, and collateral damage in gelatin and cornea as a function of laser wavelength (6.09, 6.27, or 6.43 μm), pulse energy (up to 3 mJ/pulse), and spot diameter (100 to 600 μm). We find modest wavelength dependence for ablation thresholds and collateral damage, with the lowest thresholds and least damage for 6.09 μm. We find a strong spot-size dependence for all metrics. When the beam is tightly focused (˜100-μm diameter), ablation requires more energy, is highly variable and less efficient, and can yield large zones of mechanical damage (for pulse energies >1 mJ). When the beam is softly focused (˜300-μm diameter), ablation proceeded at surgically relevant etch rates, with reasonable reproducibility (5% to 12% within a single sample), and little collateral damage. With improvements in pulse-energy stability, this prototype laser may have significant potential for soft-tissue surgical applications.

  3. Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser.

    PubMed

    Kozub, John A; Shen, Jin-H; Joos, Karen M; Prasad, Ratna; Hutson, M Shane

    2015-10-01

    Previous research showed that mid-infrared free-electron lasers could reproducibly ablate soft tissue with little collateral damage. The potential for surgical applications motivated searches for alternative tabletop lasers providing thermally confined pulses in the 6- to-7-µm wavelength range with sufficient pulse energy, stability, and reliability. Here, we evaluate a prototype Raman-shifted alexandrite laser. We measure ablation thresholds, etch rates, and collateral damage in gelatin and cornea as a function of laser wavelength (6.09, 6.27, or 6.43 µm), pulse energy (up to 3 mJ/pulse), and spot diameter (100 to 600 µm). We find modest wavelength dependence for ablation thresholds and collateral damage, with the lowest thresholds and least damage for 6.09 µm. We find a strong spot-size dependence for all metrics. When the beam is tightly focused (~100-µm diameter), ablation requires more energy, is highly variable and less efficient, and can yield large zones of mechanical damage (for pulse energies>1 mJ). When the beam is softly focused (~300-µm diameter), ablation proceeded at surgically relevant etch rates, with reasonable reproducibility (5% to 12% within a single sample), and little collateral damage. With improvements in pulse-energy stability, this prototype laser may have significant potential for soft-tissue surgical applications. PMID:26456553

  4. Atrial Fibrillation Ablation and Stroke.

    PubMed

    Aagaard, Philip; Briceno, David; Csanadi, Zoltan; Mohanty, Sanghamitra; Gianni, Carola; Trivedi, Chintan; Nagy-Baló, Edina; Danik, Stephan; Barrett, Conor; Santoro, Francesco; Burkhardt, J David; Sanchez, Javier; Natale, Andrea; Di Biase, Luigi

    2016-05-01

    Catheter ablation has become a widely available and accepted treatment to restore sinus rhythm in atrial fibrillation patients who fail antiarrhythmic drug therapy. Although generally safe, the procedure carries a non-negligible risk of complications, including periprocedural cerebral insults. Uninterrupted anticoagulation, maintenance of an adequate ACT during the procedure, and measures to avoid and detect thrombus build-up on sheaths and atheters during the procedure, appears useful to reduce the risk of embolic events. This is a review of the incidence, mechanisms, impact, and methods to reduce catheter ablation related cerebral insults. PMID:27150179

  5. 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.

  6. Possible role for cryoballoon ablation of right atrial appendage tachycardia when conventional ablation fails.

    PubMed

    Amasyali, Basri; Kilic, Ayhan

    2015-06-01

    Focal atrial tachycardia arising from the right atrial appendage usually responds well to radiofrequency ablation; however, successful ablation in this anatomic region can be challenging. Surgical excision of the right atrial appendage has sometimes been necessary to eliminate the tachycardia and prevent or reverse the resultant cardiomyopathy. We report the case of a 48-year-old man who had right atrial appendage tachycardia resistant to multiple attempts at ablation with use of conventional radiofrequency energy guided by means of a 3-dimensional mapping system. The condition led to cardiomyopathy in 3 months. The arrhythmia was successfully ablated with use of a 28-mm cryoballoon catheter that had originally been developed for catheter ablation of paroxysmal atrial fibrillation. To our knowledge, this is the first report of cryoballoon ablation without isolation of the right atrial appendage. It might also be an alternative to epicardial ablation or surgery when refractory atrial tachycardia originates from the right atrial appendage.

  7. Real time assessment of RF cardiac tissue ablation with optical spectroscopy

    SciTech Connect

    Demos, S G; Sharareh, S

    2008-03-20

    An optical spectroscopy approach is demonstrated allowing for critical parameters during RF ablation of cardiac tissue to be evaluated in real time. The method is based on incorporating in a typical ablation catheter transmitting and receiving fibers that terminate at the tip of the catheter. By analyzing the spectral characteristics of the NIR diffusely reflected light, information is obtained on such parameters as, catheter-tissue proximity, lesion formation, depth of penetration of the lesion, formation of char during the ablation, formation of coagulum around the ablation site, differentiation of ablated from healthy tissue, and recognition of micro-bubble formation in the tissue.

  8. Image-based modeling and characterization of RF ablation lesions in cardiac arrhythmia therapy

    NASA Astrophysics Data System (ADS)

    Linte, Cristian A.; Camp, Jon J.; Rettmann, Maryam E.; Holmes, David R.; Robb, Richard A.

    2013-03-01

    In spite of significant efforts to enhance guidance for catheter navigation, limited research has been conducted to consider the changes that occur in the tissue during ablation as means to provide useful feedback on the progression of therapy delivery. We propose a technique to visualize lesion progression and monitor the effects of the RF energy delivery using a surrogate thermal ablation model. The model incorporates both physical and physiological tissue parameters, and uses heat transfer principles to estimate temperature distribution in the tissue and geometry of the generated lesion in near real time. The ablation model has been calibrated and evaluated using ex vivo beef muscle tissue in a clinically relevant ablation protocol. To validate the model, the predicted temperature distribution was assessed against that measured directly using fiberoptic temperature probes inserted in the tissue. Moreover, the model-predicted lesions were compared to the lesions observed in the post-ablation digital images. Results showed an agreement within 5°C between the model-predicted and experimentally measured tissue temperatures, as well as comparable predicted and observed lesion characteristics and geometry. These results suggest that the proposed technique is capable of providing reasonably accurate and sufficiently fast representations of the created RF ablation lesions, to generate lesion maps in near real time. These maps can be used to guide the placement of successive lesions to ensure continuous and enduring suppression of the arrhythmic pathway.

  9. Model to predict the melting and ablation of reactive metal shrapnel in a high Weber number environment

    SciTech Connect

    Connell, L.W.

    1984-05-01

    Aerothermoballistic behavior of pyrophoric metal shrapnel ejected at supersonic speeds has been numerically simulated. The theoretical model predicts aerodynamic and chemical heat-transfer rates and particle thermal response, including time and position of melt initiation. Because of the high Weber number environment, the melting particle undergoes liquid layer stripping. The model, incorporated in the PLUTO computer code, predicts the liquid mass loss rate, characteristic liquid droplet diameter, temperature rise across the liquid film, and the coupled particle trajectory. The aeroheating, thermal, and ballistic sections of the PLUTO code have been validated by comparison with independent calculations and qualitative experimental data concerning the melting and ablation of gold microspheres. The model still needs to be field tested against reactive metal particles in high Weber number flows.

  10. Toward Online Modeling for Lesion Visualization and Monitoring in Cardiac Ablation Therapy

    PubMed Central

    Linte, Cristian A.; Camp, Jon J.; Holmes, David R.; Rettmann, Maryam E.; Robb, Richard A.

    2015-01-01

    Despite extensive efforts to enhance catheter navigation, limited research has been done to visualize and monitor the tissue lesions created during ablation in the attempt to provide feedback for effective therapy. We propose a technique to visualize the temperature distribution and extent of induced tissue injury via an image-based model that uses physiological tissue parameters and relies on heat transfer principles to characterize lesion progression in near real time. The model was evaluated both numerically and experimentally using ex vivo bovine muscle samples while emulating a clinically relevant ablation protocol. Results show agreement to within 5°C between the model-predicted and experimentally measured end-ablation tissue temperatures, as well as comparable predicted and observed lesion characteristics. The model yields temperature and lesion updates in near real-time, thus providing reasonably accurate and sufficiently fast monitoring for effective therapy. PMID:24505643

  11. Nonequilibrium Ablation of Phenolic Impregnated Carbon Ablator

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.; Chen, Yih K.; Gokcen, Tahir

    2012-01-01

    In previous work, an equilibrium ablation and thermal response model for Phenolic Impregnated Carbon Ablator was developed. In general, over a wide range of test conditions, model predictions compared well with arcjet data for surface recession, surface temperature, in-depth temperature at multiple thermocouples, and char depth. In this work, additional arcjet tests were conducted at stagnation conditions down to 40 W/sq cm and 1.6 kPa. The new data suggest that nonequilibrium effects become important for ablation predictions at heat flux or pressure below about 80 W/sq cm or 10 kPa, respectively. Modifications to the ablation model to account for nonequilibrium effects are investigated. Predictions of the equilibrium and nonequilibrium models are compared with the arcjet data.

  12. Radiofrequency Ablation of Colorectal Liver Metastases: Small Size Favorably Predicts Technique Effectiveness and Survival

    SciTech Connect

    Veltri, Andrea Sacchetto, Paola; Tosetti, Irene; Pagano, Eva; Fava, Cesare; Gandini, Giovanni

    2008-09-15

    The objective of this study was to analyze long-term results of radiofrequency thermal ablation (RFA) for colorectal metastases (MTS), in order to evaluate predictors for adverse events, technique effectiveness, and survival. One hundred ninety-nine nonresectable MTS (0.5-8 cm; mean, 2.9 cm) in 122 patients underwent a total of 166 RFA sessions, percutaneously or during surgery. The technique was 'simple' or 'combined' with vascular occlusion. The mean follow-up time was 24.2 months. Complications, technique effectiveness, and survival rates were statistically analyzed. Adverse events occurred in 8.1% of lesions (major complication rate: 1.1%), 7.1% with simple and 16.7% with combined technique (p = 0.15). Early complete response was obtained in 151 lesions (81.2%), but 49 lesions (26.3%) recurred locally after a mean of 10.4 months. Sustained complete ablation was achieved in 66.7% of lesions {<=}3 cm versus 33.3% of lesions >3 cm (p < 0.0001). Survival rates at 1, 3, and 5 years were 91%, 54%, and 33%, respectively, from the diagnosis of MTS and 79%, 38%, and 22%, respectively, from RFA. Mean survival time from RFA was 31.5 months, 36.2 in patients with main MTS {<=}3 cm and 23.2 in those with at least one lesion >3 cm (p = 0.006). We conclude that 'simple' RFA is safe and successful for MTS {<=}3 cm, contributing to prolong survival when patients can be completely treated.

  13. Does Heparin Coating Improve Patency or Reduce Infection of Tunneled Dialysis Catheters?

    PubMed Central

    Jain, Gaurav; Allon, Michael; Saddekni, Souheil; Barker, Jill-Finkel

    2009-01-01

    Background and objectives: Tunneled dialysis catheters are prone to frequent malfunction and infection. Catheter thrombosis occurs despite prophylactic anticoagulant locks. Catheter thrombi may also serve as a nidus for catheter infection, thereby increasing the risk of bacteremia. Thus, heparin coating of catheters may reduce thrombosis and infection. This study evaluated whether heparin-coated hemodialysis catheters have fewer infections or greater cumulative survival than noncoated catheters. Design, setting, participants, & measurements: We retrospectively queried a prospective access database to analyze the outcomes of 175 tunneled dialysis catheters placed in the internal jugular vein, including 89 heparin-coated catheters and 86 noncoated catheters. The primary outcome was cumulative catheter survival, and the secondary outcome was infection-free catheter survival. Results: The two patient groups were similar in demographics and clinical and catheter features. Catheter-related bacteremia occurred less frequently with heparin-coated catheters than with noncoated catheters (34 versus 60%, P < 0.001). Cumulative catheter survival was similar in heparin-coated and noncoated catheters (hazard ratio, 0.87; 95% confidence interval, 0.55 to 1.36; P = 0.53). On multiple variable survival analysis including catheter type, age, sex, diabetes, coronary artery disease, peripheral vascular disease, cerebrovascular disease, catheter location, and previous catheter, only catheter location predicted cumulative catheter survival (hazard ratio, 2.03; 95% CI, 1.27 to 3.25, with the right internal jugular location being the reference group, P = 0.003). The frequency of thrombolytic instillation was 1.8 per 1000 catheter-days in both groups. Conclusions: Heparin coating decreases the frequency of catheter-related bacteremia but does not reduce the frequency of catheter malfunction. PMID:19729425

  14. 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

  15. 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

  16. Common Genetic Variants and Response to Atrial Fibrillation Ablation

    PubMed Central

    Shoemaker, M. Benjamin; Bollmann, Andreas; Lubitz, Steven A.; Ueberham, Laura; Saini, Harsimran; Montgomery, Jay; Edwards, Todd; Yoneda, Zachary; Sinner, Moritz F.; Arya, Arash; Sommer, Philipp; Delaney, Jessica; Goyal, Sandeep K.; Saavedra, Pablo; Kanagasundram, Arvindh; Whalen, S. Patrick; Roden, Dan M.; Hindricks, Gerhard; Ellis, Christopher R.; Ellinor, Patrick T.; Darbar, Dawood; Husser, Daniela

    2016-01-01

    Background Common single nucleotide polymorphisms (SNPs) at chromosomes 4q25 (rs2200733, rs10033464 near PITX2), 1q21 (rs13376333 in KCNN3), and 16q22 (rs7193343 in ZFHX3) have consistently been associated with the risk of atrial fibrillation (AF). Single-center studies have shown that 4q25 risk alleles predict recurrence of AF after catheter ablation of AF. Here, we performed a meta-analysis to test the hypothesis that these 4 AF susceptibility SNPs modulate response to AF ablation. Methods and Results Patients underwent de novo AF ablation between 2008 and 2012 at Vanderbilt University, the Heart Center Leipzig, and Massachusetts General Hospital. The primary outcome was 12-month recurrence, defined as an episode of AF, atrial flutter, or atrial tachycardia lasting >30 seconds after a 3-month blanking period. Multivariable analysis of the individual cohorts using a Cox proportional hazards model was performed. Summary statistics from the 3 centers were analyzed using fixed effects meta-analysis. A total of 991 patients were included (Vanderbilt University, 245; Heart Center Leipzig, 659; and Massachusetts General Hospital, 87). The overall single procedure 12-month recurrence rate was 42%. The overall risk allele frequency for these SNPs ranged from 12% to 35%. Using a dominant genetic model, the 4q25 SNP, rs2200733, predicted a 1.4-fold increased risk of recurrence (adjusted hazard ratio, 1.3 [95% confidence intervals, 1.1–1.6]; P=0.011). The remaining SNPs, rs10033464 (4q25), rs13376333 (1q21), and rs7193343 (16q22) were not significantly associated with recurrence. Conclusions Among the 3 genetic loci most strongly associated with AF, the chromosome 4q25 SNP rs2200733 is significantly associated with recurrence of atrial arrhythmias after catheter ablation for AF. PMID:25684755

  17. Method and apparatus for guiding ablative therapy of abnormal biological electrical excitation

    NASA Technical Reports Server (NTRS)

    Armoundas, Antonis A. (Inventor); Feldman, Andrew B. (Inventor); Sherman, Derin A. (Inventor); Cohen, Richard J. (Inventor)

    2001-01-01

    This invention involves method and apparatus for guiding ablative therapy of abnormal biological electrical excitation. In particular, it is designed for treatment of cardiac arrhythmias. In the method of this invention electrical signals are acquired from passive electrodes, and an inverse dipole method is used to identify the site of origin of an arrhytmia. The location of the tip of the ablation catheter is similarly localized from signals acquired from the passive electrodes while electrical energy is delivered to the tip of the catheter. The catheter tip is then guided to the site of origin of the arrhythmia, and ablative radio frequency energy is delivered to its tip to ablate the site.

  18. Ablation of a therapy-resistant posteroseptal accessory atrioventricular pathway: going for gold.

    PubMed

    McCann, Conor J; Gal, Benjamin; Geelen, Peter

    2010-04-01

    Posteroseptal accessory pathways are sometimes resistant to ablation because of the complex anatomy of this region. Ex-vivo experiments have demonstrated that gold-tip radiofrequency ablation catheters create deeper lesions than conventional platinum-iridium tip catheters. This case of a 62-year-old man with Wolf-Parkinson-White syndrome illustrates that the ability to create such lesions can be a very useful option when previous attempts with platinum-iridium tip catheters have failed.

  19. Presternal peritoneal catheter.

    PubMed

    Twardowski, Zbylut J

    2002-04-01

    The swan neck presternal catheter is composed of 2 flexible (silicon rubber) tubes joined by a titanium connector at the time of implantation. The exit site is located in the parasternal area. The catheter located on the chest was designed to reduce the incidence of exit site infections compared to peritoneal dialysis catheters with abdominal exits. From August 1991 to September 30, 2001, 974 swan neck presternal catheters were implanted worldwide. At the university of Missouri, 150 of these catheters were implanted and followed for over 130 patient years. Presternal catheters tended to perform better than swan neck abdominal catheters regarding exit and tunnel infections, even though they were implanted in several patients in whom regular catheters with the exit on the abdomen would be difficult or impossible to implant. Two-year survival probability of presternal catheters was 0.95. Recurrent/refractory peritonitis was the only reason for catheter failure. The catheter is particularly useful in obese patients (body mass index >35), patients with ostomies, children with diapers and fecal incontinence, and patients who want to take baths without the risk of exit contamination. Many patients prefer presternal catheter because of better body image. Disadvantages of the presternal catheter are minimal. Compared with abdominal catheters, dialysis-solution flow is slightly slower because of the increased catheter length; however, slower flow is insignificant clinically. There is a possibility of catheter disconnection in the tunnel, but this complication is extremely rare in adults and easily corrected. Finally, the implantation technique is more challenging compared with that of single-piece, abdominal catheters. PMID:12085389

  20. Biopsy catheter (image)

    MedlinePlus

    ... examination, a heart biopsy can be performed. A catheter is carefully threaded into an artery or vein to gain access into the heart. A bioptome (catheter with jaws in its tip) is then introduced. ...

  1. Central venous catheters - ports

    MedlinePlus

    Central venous catheter - subcutaneous; Port-a-Cath; InfusaPort; PasPort; Subclavian port; Medi - port; Central venous line - port ... Catheters are used when you need medical treatment over a long period of time. For example, you ...

  2. Lymphocyte-to-monocyte ratio predicts survival after radiofrequency ablation for colorectal liver metastases

    PubMed Central

    Facciorusso, Antonio; Del Prete, Valentina; Crucinio, Nicola; Serviddio, Gaetano; Vendemiale, Gianluigi; Muscatiello, Nicola

    2016-01-01

    AIM: To test the correlation between lymphocyte-to-monocyte ratio (LMR) and survival after radiofrequency ablation (RFA) for colorectal liver metastasis (CLMs). METHODS: From July 2003 to Feb 2012, 127 consecutive patients with 193 histologically-proven unresectable CLMs were treated with percutaneous RFA at the University of Foggia. All patients had undergone primary colorectal tumor resection before RFA and received systemic chemotherapy. LMR was calculated by dividing lymphocyte count by monocyte count assessed at baseline. Treatment-related toxicity was defined as any adverse events occurred within 4 wk after the procedure. Overall survival (OS) and time to recurrence (TTR) were estimated from the date of RFA by Kaplan-Meier with plots and median (95%CI). The inferential analysis for time to event data was conducted using the Cox univariate and multivariate regression model to estimate hazard ratios (HR) and 95%CI. Statistically significant variables from the univariate Cox analysis were considered for the multivariate models. RESULTS: Median age was 66 years (range 38-88) and patients were prevalently male (69.2%). Median LMR was 4.38% (0.79-88) whereas median number of nodules was 2 (1-3) with a median maximum diameter of 27 mm (10-45). Median OS was 38 mo (34-53) and survival rate (SR) was 89.4%, 40.4% and 33.3% at 1, 4 and 5 years respectively in the whole cohort. Running log-rank test analysis found 3.96% as the most significant prognostic cut-off point for LMR and stratifying the study population by this LMR value median OS resulted 55 mo (37-69) in patients with LMR > 3.96% and 34 (26-39) mo in patients with LMR ≤ 3.96% (HR = 0.53, 0.34-0.85, P = 0.007). Nodule size and LMR were the only significant predictors for OS in multivariate analysis. Median TTR was 29 mo (22-35) with a recurrence-free survival (RFS) rate of 72.6%, 32.1% and 21.8% at 1, 4 and 5 years, respectively in the whole study group. Nodule size and LMR were confirmed as significant

  3. 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.

  4. The transponder system: a new method of precise catheter placement in the right atrium under echocardiographic guidance.

    PubMed

    Landzberg, J S; Franklin, J O; Langberg, J J; Herre, J M; Scheinman, M M; Schiller, N B

    1988-09-01

    The ability to localize catheters within the heart has gained importance with the use of percutaneous catheter ablation and the transseptal approach for valvuloplasty. A prototype interactive transponder catheter system, specifically designed to mark the catheter tip for echocardiographic visualization, was used to place catheters at the tricuspid anulus and the fossa ovalis in anesthetized dogs. Catheter tip location was marked by lesions produced by radiofrequency energy delivered at the distal catheter electrode. At autopsy, the center of the radiofrequency-induced lesion was located 2.8 +/- 0.7 mm from the edge of the lateral tricuspid anulus and 3.5 +/- 3.1 mm from the center of the fossa ovalis. The transponder catheter system offers the ability to precisely position catheters in the right atrium under echocardiographic guidance.

  5. Epicardial Ablation of Ventricular Tachycardia

    PubMed Central

    Tung, Roderick; Shivkumar, Kalyanam

    2015-01-01

    Epicardial mapping and ablation via a percutaneous subxiphoid technique has been instrumental in improving the working understanding of complex myocardial scars in various arrhythmogenic substrates. Endocardial ablation alone may not be sufficient in patients with ischemic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, and Chagas disease to prevent recurrent ventricular tachycardia. Multiple observational studies have demonstrated greater freedom from recurrence with adjunctive epicardial ablation compared with endocardial ablation alone. While epicardial ablation is performed predominantly at tertiary referral centers, knowledge of the technical approach, clinical indications, and potential complications is imperative to maximizing clinical success and patient safety. In 1996, Sosa and colleagues modified the pericardiocentesis technique to enable percutaneous access to the pericardial space for mapping and catheter ablation of ventricular tachycardia.1 Originally developed for patients with epicardial scarring due to chagasic cardiomyopathy and patients with ischemic cardiomyopathy refractory to endocardial ablationm,2,3 this approach has since become an essential part of the armamentarium for the treatment of ventricular tachycardia. Myocardial scars are three-dimensionally complex with varying degrees of transmurality, and the ability to map and ablate the epicardial surface has contributed to a greater understanding of scar-related VT in postinfarction cardiomyopathy and nonischemic substrates including idiopathic dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, and chagasic cardiomyopathy. In this review, we highlight the percutaneous approach and discuss clinical indications and potential complications. PMID:26306131

  6. 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.

  7. Early prediction of tumor recurrence based on CT texture changes after stereotactic ablative radiotherapy (SABR) for lung cancer

    SciTech Connect

    Mattonen, Sarah A.; Palma, David A.; Haasbeek, Cornelis J. A.; Senan, Suresh; Ward, Aaron D.

    2014-03-15

    Purpose: Benign computed tomography (CT) changes due to radiation induced lung injury (RILI) are common following stereotactic ablative radiotherapy (SABR) and can be difficult to differentiate from tumor recurrence. The authors measured the ability of CT image texture analysis, compared to more traditional measures of response, to predict eventual cancer recurrence based on CT images acquired within 5 months of treatment. Methods: A total of 24 lesions from 22 patients treated with SABR were selected for this study: 13 with moderate to severe benign RILI, and 11 with recurrence. Three-dimensional (3D) consolidative and ground-glass opacity (GGO) changes were manually delineated on all follow-up CT scans. Two size measures of the consolidation regions (longest axial diameter and 3D volume) and nine appearance features of the GGO were calculated: 2 first-order features [mean density and standard deviation of density (first-order texture)], and 7 second-order texture features [energy, entropy, correlation, inverse difference moment (IDM), inertia, cluster shade, and cluster prominence]. For comparison, the corresponding response evaluation criteria in solid tumors measures were also taken for the consolidation regions. Prediction accuracy was determined using the area under the receiver operating characteristic curve (AUC) and two-fold cross validation (CV). Results: For this analysis, 46 diagnostic CT scans scheduled for approximately 3 and 6 months post-treatment were binned based on their recorded scan dates into 2–5 month and 5–8 month follow-up time ranges. At 2–5 months post-treatment, first-order texture, energy, and entropy provided AUCs of 0.79–0.81 using a linear classifier. On two-fold CV, first-order texture yielded 73% accuracy versus 76%–77% with the second-order features. The size measures of the consolidative region, longest axial diameter and 3D volume, gave two-fold CV accuracies of 60% and 57%, and AUCs of 0.72 and 0.65, respectively

  8. Predicting Radiation Pneumonitis After Stereotactic Ablative Radiation Therapy in Patients Previously Treated With Conventional Thoracic Radiation Therapy

    SciTech Connect

    Liu Hui; Zhang Xu; Vinogradskiy, Yevgeniy Y.; Swisher, Stephen G.; Komaki, Ritsuko; Chang, Joe Y.

    2012-11-15

    Purpose: To determine the incidence of and risk factors for radiation pneumonitis (RP) after stereotactic ablative radiation therapy (SABR) to the lung in patients who had previously undergone conventional thoracic radiation therapy. Methods and Materials: Seventy-two patients who had previously received conventionally fractionated radiation therapy to the thorax were treated with SABR (50 Gy in 4 fractions) for recurrent disease or secondary parenchymal lung cancer (T <4 cm, N0, M0, or Mx). Severe (grade {>=}3) RP and potential predictive factors were analyzed by univariate and multivariate logistic regression analyses. A scoring system was established to predict the risk of RP. Results: At a median follow-up time of 16 months after SABR (range, 4-56 months), 15 patients had severe RP (14 [18.9%] grade 3 and 1 [1.4%] grade 5) and 1 patient (1.4%) had a local recurrence. In univariate analyses, Eastern Cooperative Oncology Group performance status (ECOG PS) before SABR, forced expiratory volume in 1 second (FEV1), and previous planning target volume (PTV) location were associated with the incidence of severe RP. The V{sub 10} and mean lung dose (MLD) of the previous plan and the V{sub 10}-V{sub 40} and MLD of the composite plan were also related to RP. Multivariate analysis revealed that ECOG PS scores of 2-3 before SABR (P=.009), FEV1 {<=}65% before SABR (P=.012), V{sub 20} {>=}30% of the composite plan (P=.021), and an initial PTV in the bilateral mediastinum (P=.025) were all associated with RP. Conclusions: We found that severe RP was relatively common, occurring in 20.8% of patients, and could be predicted by an ECOG PS score of 2-3, an FEV1 {<=}65%, a previous PTV spanning the bilateral mediastinum, and V{sub 20} {>=}30% on composite (previous RT+SABR) plans. Prospective studies are needed to validate these predictors and the scoring system on which they are based.

  9. Real-time x-ray fluoroscopy-based catheter detection and tracking for cardiac electrophysiology interventions

    SciTech Connect

    Ma Yingliang; Housden, R. James; Razavi, Reza; Rhode, Kawal S.; Gogin, Nicolas; Cathier, Pascal; Gijsbers, Geert; Cooklin, Michael; O'Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo

    2013-07-15

    Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 {+-} 0.29, 0.92 {+-} 0.61, and 0.63 {+-} 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 {+-} 0.28, 0.64 {+-} 0.37, and 0.53 {+-} 0.38 mm and success rates increased to 100%, 99

  10. Problems of indwelling Foley catheters.

    PubMed

    Ndirangu, K; Ngugi, M

    1994-02-01

    One hundred patients undergoing urinary bladder catheterization for various reasons were studied. 42 patients received Sewoon catheters of various sizes. 38 received Eschmann catheters of various sizes and 20 received Bard catheters of various sizes. The duration of catheterization ranged from a few hours to 21 days. Various problems associated with catheterization were recorded whenever encountered. Stuck catheter was found to occur in 15 of the 40 patients who received Sewoon catheters. There were no stuck catheters recorded for Eschmann or Bard catheters. Infections occurred in 9 out of 100 patients, 7 of whom had Sewoon catheters. Leakage was recorded in 12 of the 100 patients, 9 of whom had Sewoon catheters. Blockage of balloon occurred in 5 patients, 3 of whom had Sewoon catheters. Painful spasms occurred in 8 patients, 4 with Bard, 4 with Sewoon catheters. It is concluded that Sewoon type of Foley catheters was associated with more problems than the other types studied.

  11. Three Dimensional Modeling of an MRI Actuated Steerable Catheter System.

    PubMed

    Liu, Taoming; Cavuşoğlu, M Cenk

    2014-01-01

    This paper presents the three dimensional kinematic modeling of a novel steerable robotic ablation catheter system. The catheter, embedded with a set of current-carrying micro-coils, is actuated by the magnetic forces generated by the magnetic field of the MRI scanner. This paper develops a 3D model of the MRI actuated steerable catheter system by using finite differences approach. For each finite segment, a quasi-static torque-deflection equilibrium equation is calculated using beam theory. By using the deflection displacements and torsion angles, the kinematic modeling of the catheter system is derived. The proposed models are evaluated by comparing the simulation results of the proposed model with the experimental results of a proof-of-concept prototype. PMID:25328804

  12. [Suprapubic catheter insertion].

    PubMed

    Neumann, Eva; Schwentner, Christian

    2016-01-01

    The suprapubic catheter enables a percutaneous drainage of urine. The insertion is made superior of the pubic bone through the abdominal wall into the bladder. It allows a permanent drainage of urine bypassing the urethra. The insertion of a suprapubic catheter requires knowledge and expertise. This paper summarizes the basic background and allows to follow the practical application step by step.

  13. [Suprapubic catheter insertion].

    PubMed

    Neumann, Eva; Schwentner, Christian

    2016-01-01

    The suprapubic catheter enables a percutaneous drainage of urine. The insertion is made superior of the pubic bone through the abdominal wall into the bladder. It allows a permanent drainage of urine bypassing the urethra. The insertion of a suprapubic catheter requires knowledge and expertise. This paper summarizes the basic background and allows to follow the practical application step by step. PMID:26800072

  14. Suprapubic catheter removal: the cuffing effect of deflated catheter balloons.

    PubMed

    Robinson, John

    2003-05-01

    Supra-pubic catheterization plays an important role in patient care and management when this method of indwelling catheterization is required. However, one area of concern often experienced by nurses is the problem removing supra-pubic catheters or not being able to remove it. Catheter balloons, when deflated, incur crease or ridge formation. Removing supra-pubic catheters, a 'cuffing' effect occurs as the catheter is being removed. This seems to affect 100% silicone catheters more than non-silicone catheters. This article looks at the changes 100% silicone catheter balloons undergo following deflation and removal.

  15. Conducting polymer based active catheter for minimally invasive interventions inside arteries.

    PubMed

    Shoa, Tina; Madden, John D; Fekri, Niloofar; Munce, Nigel R; Yang, Victor X D

    2008-01-01

    An active catheter intended for controllable intravascular maneuvers is presented and initial experimental results are shown. A commercial catheter is coated with polypyrrole and laser micromachined into electrodes, which are electrochemically activated, leading to bending of the catheter. The catheter's electro-chemo-mechanical properties are theoretically modeled to design the first prototype device, and used to predict an optimal polypyrrole thickness for the desired degree of bending within approximately 30 seconds. We compared the experimental result of catheter bending to the theoretical model with estimated electrochemical strain, showing reasonable agreement. Finally, we used the model to design an encapsulated catheter with polypyrrole actuation for improved intravascular compatibility and performance.

  16. 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 ...

  17. Central venous catheter - flushing

    MedlinePlus

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

  18. Indwelling catheter care

    MedlinePlus

    ... Common reasons to have an indwelling catheter are urinary incontinence (leakage), urinary retention (not being able to urinate), ... gov/pubmed/22094023 . Read More Radical prostatectomy Stress urinary incontinence Transurethral resection of the prostate Urge incontinence Urinary ...

  19. Suprapubic catheter care

    MedlinePlus

    ... You may need a catheter because you have urinary incontinence (leakage), urinary retention (not being able to urinate), ... vaginal wall repair Inflatable artificial sphincter Radical prostatectomy Urinary incontinence - injectable implant Urinary incontinence - retropubic suspension Urinary incontinence - ...

  20. [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.

  1. Catheter tracking in asynchronous biplane fluoroscopy images by 3D B-snakes

    NASA Astrophysics Data System (ADS)

    Schenderlein, Marcel; Stierlin, Susanne; Manzke, Robert; Rasche, Volker; Dietmayer, Klaus

    2010-02-01

    Minimally invasive catheter ablation procedures are guided by biplane fluoroscopy images visualising the interventional scene from two different orientations. However, these images do not provide direct access to their inherent spatial information. A three-dimensional reconstruction and visualisation of the catheters from such projections has the potential to support quick and precise catheter navigation. It enhances the perception of the interventional situation and provides means of three-dimensional catheter pose documentation. In this contribution we develop an algorithm for tracking the three-dimensional pose of electro-physiological catheters in biplane fluoroscopy images. It is based on the B-Snake algorithm which had to be adapted to the biplane and in particular the asynchronous image acquisition situation. A three-dimensional B-spline curve is transformed so that its projections are consistent with the catheter path enhancing feature images, while the information from the missing image caused by the asynchronous acquisition is interpolated from its sequence neighbours. In order to analyse the three-dimensional precision, virtual images were created from patient data sets and threedimensional ground truth catheter paths. The evaluation of the three-dimensional catheter pose reconstruction by means of our algorithm on 33 of such virtual image sets indicated a mean catheter pose error of 1.26 mm and a mean tip deviation of 3.28 mm. The tracking capability of the algorithm was evaluated on 10 patient data sets. In 94 % of all images our algorithm followed the catheter projections.

  2. Transcatheter and ablative therapeutic approaches for solid malignancies.

    PubMed

    Liapi, Eleni; Geschwind, Jean-Francois H

    2007-03-10

    The purpose of this article is to present in a concise manner an overview of the most widely used locoregional transcatheter and ablative therapies for solid malignancies. An extensive MEDLINE search was performed for this review. Therapies used for liver cancer were emphasized because these therapies are used most commonly in the liver. Applications in pulmonary, renal, and bone tumors were also discussed. These approaches were divided into catheter-based therapies (such as transcatheter arterial chemoembolization, bland embolization, and the most recent transcatheter arterial approach with drug-eluting microspheres), ablative therapies (such as chemical [ethanol or acetic acid injection]), and thermal ablative therapies (such as radiofrequency ablation, laser induced thermotherapy, microwave ablation, cryoablation, and extracorporeal high-intensity focused ultrasound ablation). A brief description of each technique and analysis of available data was reported for all therapies. Locoregional transcatheter and ablative therapies continue to be used mostly for palliation, but have also been used with curative intent. A growing body of evidence suggests clear survival benefit, excellent results regarding local tumor control, and improved quality of life. Clinical trials are underway to validate these results. Image-guided transcatheter and ablative approaches currently play an important role in the management of patients with various types of cancer-a role that is likely to grow even more given the technological advances in imaging, image-guidance systems, catheters, ablative tools, and drug delivery systems. As a result, the outcomes of patients with cancer undoubtedly will improve.

  3. Automated planning of ablation targets in atrial fibrillation treatment

    NASA Astrophysics Data System (ADS)

    Keustermans, Johannes; De Buck, Stijn; Heidbüchel, Hein; Suetens, Paul

    2011-03-01

    Catheter based radio-frequency ablation is used as an invasive treatment of atrial fibrillation. This procedure is often guided by the use of 3D anatomical models obtained from CT, MRI or rotational angiography. During the intervention the operator accurately guides the catheter to prespecified target ablation lines. The planning stage, however, can be time consuming and operator dependent which is suboptimal both from a cost and health perspective. Therefore, we present a novel statistical model-based algorithm for locating ablation targets from 3D rotational angiography images. Based on a training data set of 20 patients, consisting of 3D rotational angiography images with 30 manually indicated ablation points, a statistical local appearance and shape model is built. The local appearance model is based on local image descriptors to capture the intensity patterns around each ablation point. The local shape model is constructed by embedding the ablation points in an undirected graph and imposing that each ablation point only interacts with its neighbors. Identifying the ablation points on a new 3D rotational angiography image is performed by proposing a set of possible candidate locations for each ablation point, as such, converting the problem into a labeling problem. The algorithm is validated using a leave-one-out-approach on the training data set, by computing the distance between the ablation lines obtained by the algorithm and the manually identified ablation points. The distance error is equal to 3.8+/-2.9 mm. As ablation lesion size is around 5-7 mm, automated planning of ablation targets by the presented approach is sufficiently accurate.

  4. Theoretical Modeling for Hepatic Microwave Ablation

    PubMed Central

    Prakash, Punit

    2010-01-01

    Thermal tissue ablation is an interventional procedure increasingly being used for treatment of diverse medical conditions. Microwave ablation is emerging as an attractive modality for thermal therapy of large soft tissue targets in short periods of time, making it particularly suitable for ablation of hepatic and other tumors. Theoretical models of the ablation process are a powerful tool for predicting the temperature profile in tissue and resultant tissue damage created by ablation devices. These models play an important role in the design and optimization of devices for microwave tissue ablation. Furthermore, they are a useful tool for exploring and planning treatment delivery strategies. This review describes the status of theoretical models developed for microwave tissue ablation. It also reviews current challenges, research trends and progress towards development of accurate models for high temperature microwave tissue ablation. PMID:20309393

  5. [Radiofrequency transcatheter ablation in atrial tachycardia].

    PubMed

    Velázquez Rodríguez, E; Morales Hernández, J A

    2000-01-01

    Incessant atrial tachycardia is an infrequent arrhythmia. Specially difficult to treat medically. Radiofrequency catheter ablation has been used successfully to cure a variety of supraventricular tachycardias. The purpose of this work is to report our initial experience in the treatment of atrial tachycardia. Ten patients, mean age 28.7 +/- 15 year with conventional drug-resistant symptomatic atrial tachycardia were treated with selective ablation of the focus using radiofrequency energy. It was found an abnormal automaticity in 10 tachycardias and in only one patient intra-atrial reentrant was supported. Radiofrequency energy was successful in 10 of 11 tachycardias with a mean of 9.3 +/- 6.8 applications using the technique of local atrial electrogram activation time with a mean value of -54 +/- -31 milliseconds at the successful ablation sites. No complications were observed and one patient had an early clinical recurrence. All patients with successful ablation are symptom-free, in sinus rhythm and without antiarrhythmic medications after 1 to 28 months of follow-up. Our initial experience support that radiofrequency catheter ablation is a safe and effective therapeutic option for incessant atrial tachycardia. PMID:10855411

  6. Characterization of tracked radiofrequency ablation in phantom

    SciTech Connect

    Chen, Chun-Cheng R.; Miga, Michael I.; Galloway, Robert L.

    2007-10-15

    In radiofrequency ablation (RFA), successful therapy requires accurate, image-guided placement of the ablation device in a location selected by a predictive treatment plan. Current planning methods rely on geometric models of ablations that are not sensitive to underlying physical processes in RFA. Implementing plans based on computational models of RFA with image-guided techniques, however, has not been well characterized. To study the use of computational models of RFA in planning needle placement, this work compared ablations performed with an optically tracked RFA device with corresponding models of the ablations. The calibration of the tracked device allowed the positions of distal features of the device, particularly the tips of the needle electrodes, to be determined to within 1.4{+-}0.6 mm of uncertainty. Ablations were then performed using the tracked device in a phantom system based on an agarose-albumin mixture. Images of the sliced phantom obtained from the ablation experiments were then compared with the predictions of a bioheat transfer model of RFA, which used the positional data of the tracked device obtained during ablation. The model was demonstrated to predict 90% of imaged pixels classified as being ablated. The discrepancies between model predictions and observations were analyzed and attributed to needle tracking inaccuracy as well as to uncertainties in model parameters. The results suggest the feasibility of using finite element modeling to plan ablations with predictable outcomes when implemented using tracked RFA.

  7. Atrioventricular nodal reentrant tachycardia ablation and inferior vena cava agenesis.

    PubMed

    Galand, Vincent; Pavin, Dominique; Behar, Nathalie; Mabo, Philippe; Martins, Raphaël P

    2016-10-01

    Congenital anomalies of the inferior vena cava (IVC) are rare and very often diagnosed in asymptomatic patients during computed tomography performed for other purposes. These anomalies can have significant clinical implications, for example if electrophysiology procedures are needed. Diagnostic and ablation procedures are difficult since catheter manipulation and positioning are more complex. We present here a case of successful atrioventricular nodal reentrant tachycardia ablation in a patient with unexpected IVC agenesis, using an azygos route. PMID:27633734

  8. Serial surveillance cultures of skin and catheter hub specimens from critically ill patients with central venous catheters: molecular epidemiology of infection and implications for clinical management and research.

    PubMed Central

    Atela, I; Coll, P; Rello, J; Quintana, E; Barrio, J; March, F; Sanchez, F; Barraquer, P; Ballus, J; Cotura, A; Prats, G

    1997-01-01

    A prospective study of 45 central venous catheters was conducted to assess, by strain delineation, the turnover of skin and catheter hub (superficial) colonization and the relative contributions of catheter hub and skin colonization to catheter tip colonization. Serial quantitative cultures of skin and catheter hub were performed. Catheter tip, blood, and specimens for culture from targeted superficial sites (TSSs) were also collected at the time of catheter removal. Strains from 17 tip-positive catheters were delineated by pulsed-field gel electrophoresis. Only 12 (28.6%) of 42 skin strains and 14 (31.1%) of 45 catheter hub strains were found to be present at the time of catheter removal. In addition, only 9 (29.0%) of the 31 tip-colonizing strains were present on TSSs. Moreover, 15 (48.4%) of the 31 tip-colonizing strains had a superficial origin, and the other 16 (51.6%) were of unknown origin. In catheters suspected of infection, cultures of TSSs had a negative predictive value for catheter-related bacteremia of 94.4% but a positive predictive value of 44.4%. When the causative agent was identified (to the strain level) these values dropped to 80.9 and 18.7%, respectively. The study shows that skin and catheter hub colonization is a common, dynamic phenomenon. Strains recovered from TSSs showed a low level of correlation with strains from previous cultures of specimens from superficial sites and catheter tip isolates. Consequently, TSSs cannot be recommended for use in determining the therapy. However, catheter-related bacteremia is uncommon when cultures of TSSs are negative. PMID:9196194

  9. Occipital lobe infarction following cardiac ablation.

    PubMed

    Mirza, Rukhsana G; Biller, Jose; Jay, Walter M

    2004-01-01

    A 60-year-old man presented with the chief complaint of seeing a blurred area just up and to the left of the center of his vision. The patient noted this visual field defect immediately after he awoke from a cardiac electrophysiologic study with a catheter ablation procedure. On neuro-ophthalmologic testing, a small scotoma was present superior and left of fixation in both eyes. MRI showed a small irregular area of abnormal signal in the right occipital lobe consistent with an ischemic lesion. To the best of our knowledge, this represents the first case report of a homonymous visual field defect secondary to an occipital lobe infarction following a cardiac catheter ablation procedure.

  10. Feasibility and safety of remote-controlled magnetic navigation for ablation of atrial fibrillation.

    PubMed

    Katsiyiannis, William T; Melby, Daniel P; Matelski, Jayme L; Ervin, Vanessa L; Laverence, Kerri L; Gornick, Charles C

    2008-12-15

    Radiofrequency ablation for atrial fibrillation (AF) involves complex catheter manipulation resulting in prolonged procedure time and fluoroscopy exposure. Remote magnetic navigation (RMN) represents a novel approach toward improving the ability to perform complex ablation. Forty patients underwent ablation for AF, 20 using RMN (NIOBE II, Stereotaxis, Inc) with a 4-mm-tip magnetic catheter (Celsius, Biosense Webster) and 20 using a conventional 8-mm-tip bidirectional ablation catheter (Blazer, Boston Scientific). All patients underwent a combined wide area circumferential ablation and segmental pulmonary vein (PV) isolation using a circular mapping catheter and cavotricuspid isthmus ablation for right atrial flutter. The procedural end point was PV entrance block. There was no difference in atrial size, left ventricular systolic function, or type of AF between groups. PV entrance block was achieved in all patients. Mean procedure time was 279 +/- 60 minutes in the conventional group versus 209 +/- 56 minutes in the RMN group (p <0.001). Mean fluoroscopy time in the conventional group was 58.6 +/- 21 minutes versus 19.5 +/- 9.8 in the RMN group (p <0.001). At 1 year there were 15 patients in the conventional group and 16 in the RMN group free from clinical AF and off antiarrhythmic drugs (p = NS). There were 2 additional ablations performed for atypical atrial flutter in the conventional group and 3 in the RMN group (p = ns). Ablation catheter char formation was not observed. There were no procedural complications. In conclusion, radiofrequency ablation of AF performed with RMN is safe and feasible. Compared with conventional hand-navigated ablation, RMN ablation results in similar clinical outcomes with decreased fluoroscopy and procedure times.

  11. State-of-the-art and emerging technologies for atrial fibrillation ablation.

    PubMed

    Dewire, Jane; Calkins, Hugh

    2010-03-01

    Catheter ablation is an important treatment modality for patients with atrial fibrillation (AF). Although the superiority of catheter ablation over antiarrhythmic drug therapy has been demonstrated in middle-aged patients with paroxysmal AF, the role the procedure in other patient subgroups-particularly those with long-standing persistent AF-has not been well defined. Furthermore, although AF ablation can be performed with reasonable efficacy and safety by experienced operators, long-term success rates for single procedures are suboptimal. Fortunately, extensive ongoing research will improve our understanding of the mechanisms of AF, and considerable funds are being invested in developing new ablation technologies to improve patient outcomes. These technologies include ablation catheters designed to electrically isolate the pulmonary veins with improved safety, efficacy, and speed, catheters designed to deliver radiofrequency energy with improved precision, robotic systems to address the technological demands of the procedure, improved imaging and electrical mapping systems, and MRI-guided ablation strategies. The tools, technologies, and techniques that will ultimately stand the test of time and become the standard approach to AF ablation in the future remain unclear. However, technological advances are sure to result in the necessary improvements in the safety and efficacy of AF ablation procedures.

  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. An organized approach to the localization, mapping, and ablation of outflow tract ventricular arrhythmias.

    PubMed

    Hutchinson, Mathew D; Garcia, Fermin C

    2013-10-01

    The outflow tract (OT) regions of the right and left ventricles, common sites of origin for idiopathic ventricular arrhythmias (VA), have complex three-dimensional anatomical relationships. The understanding of in situ or "attitudinal" relationships not only informs the electrocardiographic interpretation of VA site of origin, but also facilitates their catheter-based mapping and ablation strategies. By viewing each patient as his or her own "control," the expected changes in ECG morphology (i.e., frontal plane QRS axis and precordial transition) between adjacent intracardiac structures (e.g., RVOT and aortic root) can be reliably predicted. Successful mapping of OT VAs involve a combination of activation and pacemapping guided by fluoroscopy, electroanatomical mapping, and intracardiac echocardiography. The purpose of this manuscript is to provide a simple, reliable strategy for catheter based mapping and ablation of OT VAs. We also discuss 2 specific challenges in OT VA mapping: (1) differentiating posterior RVOT from right coronary cusp VA origin; and (2) mapping VAs originating from the LV summit.

  14. Method and apparatus for the guided ablative therapy of fast ventricular arrhythmia

    NASA Technical Reports Server (NTRS)

    Cohen, Richard J. (Inventor); Barley, Maya (Inventor)

    2010-01-01

    Method and apparatus for guiding ablative therapy of abnormal biological electrical excitation. The excitation from the previous excitatory wave is significant at the beginning of the next excitation. In particular, it is designed for treatment of fast cardiac arrhythmias. Electrical signals are acquired from recording electrodes, and an inverse dipole method is used to identify the site of origin of an arrhythmia. The location of the tip of an ablation catheter is similarly localized from signals acquired from the recording electrodes while electrical pacing energy is delivered to the tip of the catheter close to or in contact with the cardiac tissue. The catheter tip is then guided to the site of origin of the arrhythmia, and ablative radio frequency energy is delivered to its tip to ablate the site.

  15. Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures

    PubMed Central

    2012-01-01

    Background One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating. Methods A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip. Results A maximum temperature rise of 22.4°C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2°C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8°C. Conclusion Up to a maximum of 22.4°C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip

  16. [Successful ablation of an atrioventricular nodal reentrant tachycardia ablation 2 years after orthotopic heart transplantation].

    PubMed

    Bellmann, Barbara; Reith, Sebastian; Gemein, Christopher; Schauerte, Patrick

    2015-09-01

    We report the case of a 48-year-old woman with an orthotopic heart transplantation. Two years after transplantation, the patient reported intermittent palpitations and dyspnea. The results of the 12-lead electrogram provided suspicion of AV nodal reentrant tachycardia (AVNRT), which was confirmed in the electrophysiological examination. The AVNRT was successfully eliminated without complications by radiofrequency catheter ablation of the slow pathway. The case shows that an AVNRT, even with existing sinus rhythm of the original heart, can also occur on the transplanted heart and ablation is safe and feasible. PMID:26208808

  17. Laser Ablation for Small Hepatocellular Carcinoma

    PubMed Central

    Pacella, Claudio Maurizio; Francica, Giampiero; Di Costanzo, Giovanni Giuseppe

    2011-01-01

    Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and is increasingly detected at small size (<5 cm) owing to surveillance programmes in high-risk patients. For these cases, curative therapies such as resection, liver transplantation, or percutaneous ablation have been proposed. When surgical options are precluded, image-guided tumor ablation is recommended as the most appropriate therapeutic choice in terms of tumor local control, safety, and improvement in survival. Laser ablation (LA) represents one of currently available loco-ablative techniques: light is delivered via flexible quartz fibers of diameter from 300 to 600 μm inserted into tumor lesion through either fine needles (21g Chiba needles) or large-bore catheters. The thermal destruction of tissue is achieved through conversion of absorbed light (usually infrared) into heat. A range of different imaging modalities have been used to guide percutaneous laser ablation, but ultrasound and magnetic resonance imaging are most widely employed, according to local experience and resource availability. Available clinical data suggest that LA is highly effective in terms of tumoricidal capability with an excellent safety profile; the best results in terms of long-term survival are obtained in early HCC so that LA can be proposed not only in unresectable cases but, not differently from radiofrequency ablation, also as the first-line treatment. PMID:22191028

  18. Pulmonary vein isolation during atrial fibrillation using a circumferential cryoablation catheter.

    PubMed

    Rostock, Thomas; Weiss, Christian; Ventura, Rodolfo; Willems, Stephan

    2004-07-01

    Pulmonary vein (PV) isolation for the treatment of atrial fibrillation is limited by procedure related complications, such as PV stenosis and occlusions. We report about a PV isolation using a circumferential cryoablation catheter which applies the ablation energy simultaneously at the entire circumference by cooling down to a minimal temperature of -80 degrees C.

  19. Catheter steering using a Magnetic Resonance Imaging system.

    PubMed

    Lalande, Viviane; Gosselin, Frederick P; Martel, Sylvain

    2010-01-01

    A catheter is successfully bent and steered by applying magnetic gradients inside a Magnetic Resonance Imaging system (MRI). One to three soft ferromagnetic spheres are attached at the distal tip of the catheter with different spacing between the spheres. Depending on the interactions between the spheres, progressive or discontinuous/jumping displacement was observed for increasing magnetic load. This phenomenon is accurately predicted by a simple theoretical dipole interaction model. PMID:21096567

  20. [Clinical study of Silver Lubricath Foley catheter].

    PubMed

    Nakada, J; Kawahara, M; Onodera, S; Oishi, Y

    1996-06-01

    We evaluated the Silver Lubricath Foley Catheter (silver catheter) coated with silver and hydrogel developed to prevent urinary infection, in comparison with the silicone-coated catheter (silicone catheter). Twelve patients ranging from 71 to 95 years of age (median age, 82 years) were catheterized and the 16 of 18F catheter was replaced every 2 weeks. They answered a questionnaire which included inquiry about the treatment with urinary catheter. Because of less leakage and discomfort to the urethra, the silver catheter had advantages over the silicone catheter. The risk of bacteriuria after 14 days of catheterization was not significantly different between the two types of catheter. Scanning electron microscopic analysis revealed that bacterial biofilm developed on the inner surface of both catheters after 14 days of catheterization. On the other hand, the amount of bacterial biofilm on the outer surface of a silver catheter was less than that on the outer surface of a silicone catheter.

  1. Ablative Thermal Protection: An Overview

    NASA Technical Reports Server (NTRS)

    Laub, Bernie

    2003-01-01

    Contents include the following: Why ablative thermal protections - TPS. Ablative TPS chronology: strategic reentry systems, solid rocket motor nozzles, space (manned missions and planetary entry probes). Ablation mechanisms. Ablation material testing. Ablative material testing.

  2. 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.

  3. Is it feasible to diagnose catheter-related candidemia without catheter withdrawal?

    PubMed

    Fernández-Cruz, Ana; Martín-Rabadán, Pablo; Suárez-Salas, Marisol; Rojas-Wettig, Loreto; Pérez, María Jesús; Guinea, Jesús; Guembe, María; Peláez, Teresa; Sánchez-Carrillo, Carlos; Bouza, Emilio

    2014-07-01

    Many bloodstream infections (BSI) in patients with central venous catheters (CVC) are not catheter-related (CR). Assessment of catheter involvement without catheter withdrawal has not been studied in candidemia. We assessed the value of conservative techniques to evaluate catheters as the origin of candidemia in patients with CVC in a prospective cohort study (superficial Gram stain and culture, Kite technique (Gram stain and culture of the first 1 cm blood drawn from the CVC), proportion of positive blood cultures (PPBCs), differential time to positivity (DTP), and minimal time to positivity (MTP)). All catheters were cultured at withdrawal. From June 2008 to January 2012, 22 cases fulfilled the inclusion criteria. CR-candidemia (CRC) was confirmed in 10. Validity values for predicting CRC were: superficial Gram stain (S, 30%; Sp, 81.83%; PPV, 60%; NPV, 56.3%; Ac, 57.1%), superficial cultures (S, 40%; Sp, 75%; PPV, 57.1%; NPV, 60%; Ac, 59.1%), Kite Gram stain (S, 33.3%; Sp, 66.7%; PPV, 50%; NPV, 50%; Ac, 50%), Kite culture (S, 80%; Sp, 66.7%; PPV, 66.7%; NPV, 80%; Ac, 72.7%), PPBC (S, 50%; Sp, 41.7%; PPV, 41.7%; NPV, 50.0%; Ac, 45.5%), DTP (S, 100%; Sp, 33.3%; PPV, 55.6%; NPV, 100%; Ac, 63.6%), and MTTP (S, 70%; Sp, 58.3%; PPV, 58.3%; NPV, 70%; Ac, 63.6%). While combinations of two tests improved sensitivity and NPV, more than two tests did not improve validity values. Classic tests to assess CR-BSI caused by bacteria cannot be reliably used to diagnose CRC. Combinations of tests could be useful, but more and larger studies are required.

  4. Excimer laser lead extraction catheter with increased laser parameters

    NASA Astrophysics Data System (ADS)

    Coe, M. Sean; Taylor, Kevin D.; Lippincott, Rebecca A.; Sorokoumov, Oleg; Papaioannou, Thanassis

    2001-05-01

    A fiber optic catheter connected to a pulsed excimer laser (308 nm) is currently used to extract chronically implanted pacemaker and defibrillator leads at Fluence of 60 mJ/mm2 and repetition rate of 40 Hz. The object of this study was to determine the effect of higher repetition rates (80 Hz) in the catheter's cutting performance. The penetration rate (micrometers /sec), and the associated mechanical and thermal effects were measured in soft (porcine myocardium) and hard tissue (bovine tendon) at 60 mJ/mm2-80 Hz, and were compared to the corresponding values at commercially available laser parameters (60 mJ/mm2-40 Hz). Ablation rates were measured with perforation experiments and the extent of thermal and mechanical damage was measured under polarized light microscopy. For hard (soft) tissue, the laser catheter demonstrated penetration speed of 106 +/- 32 (302 +/- 101) micrometers /sec at 40 Hz and 343 +/- 120 (830 +/- 364) micrometers /sec at 80 Hz. Maximum extent of thermal effects at 40 Hz and 80 Hz was 114 +/- 35 micrometers (72 +/- 18) and 233 +/- 63 micrometers (71 +/- 16) respectively. Maximum extent of mechanical effects at 40 Hz and 80 Hz was 188 +/- 63 micrometers (590 +/- 237) and 386 +/- 100 micrometers (767 +/- 160) respectively. In vitro testing of the laser catheter with 80 Hz laser parameters has demonstrated increased penetration speed in both soft and hard fibrous tissue, while maintaining associated thermal and mechanical effects within limited ranges.

  5. Predicting Overall Survival After Stereotactic Ablative Radiation Therapy in Early-Stage Lung Cancer: Development and External Validation of the Amsterdam Prognostic Model

    SciTech Connect

    Louie, Alexander V.; Haasbeek, Cornelis J.A.; Mokhles, Sahar; Rodrigues, George B.; Stephans, Kevin L.; Lagerwaard, Frank J.; Palma, David A.; Videtic, Gregory M.M.; Warner, Andrew; Takkenberg, Johanna J.M.; Reddy, Chandana A.; Maat, Alex P.W.M.; Woody, Neil M.; Slotman, Ben J.; Senan, Suresh

    2015-09-01

    Purpose: A prognostic model for 5-year overall survival (OS), consisting of recursive partitioning analysis (RPA) and a nomogram, was developed for patients with early-stage non-small cell lung cancer (ES-NSCLC) treated with stereotactic ablative radiation therapy (SABR). Methods and Materials: A primary dataset of 703 ES-NSCLC SABR patients was randomly divided into a training (67%) and an internal validation (33%) dataset. In the former group, 21 unique parameters consisting of patient, treatment, and tumor factors were entered into an RPA model to predict OS. Univariate and multivariate models were constructed for RPA-selected factors to evaluate their relationship with OS. A nomogram for OS was constructed based on factors significant in multivariate modeling and validated with calibration plots. Both the RPA and the nomogram were externally validated in independent surgical (n=193) and SABR (n=543) datasets. Results: RPA identified 2 distinct risk classes based on tumor diameter, age, World Health Organization performance status (PS) and Charlson comorbidity index. This RPA had moderate discrimination in SABR datasets (c-index range: 0.52-0.60) but was of limited value in the surgical validation cohort. The nomogram predicting OS included smoking history in addition to RPA-identified factors. In contrast to RPA, validation of the nomogram performed well in internal validation (r{sup 2}=0.97) and external SABR (r{sup 2}=0.79) and surgical cohorts (r{sup 2}=0.91). Conclusions: The Amsterdam prognostic model is the first externally validated prognostication tool for OS in ES-NSCLC treated with SABR available to individualize patient decision making. The nomogram retained strong performance across surgical and SABR external validation datasets. RPA performance was poor in surgical patients, suggesting that 2 different distinct patient populations are being treated with these 2 effective modalities.

  6. The past, the present, and the future of cardiac arrhythmia ablation.

    PubMed

    Andrade, Jason G; Rivard, Léna; Macle, Laurent

    2014-12-01

    The development and evolution of percutaneous catheter ablation for the treatment of cardiac arrhythmias has advanced significantly since the early days of direct current shock ablation, and in parallel with an increasing understanding about arrhythmia mechanisms. Because of the ever-changing landscape that is cardiac electrophysiology, the purpose of this review is to discuss the future of invasive arrhythmia management within the context of the history and contemporary practice of this cardiac subspecialty. Topics of discussion include: (1) the evolution of ablation technologies from direct current shock and radiofrequency to alternative energy sources such as cryothermal ablation; (2) the use and development of nonfluoroscopic navigation systems; (3) the progression of ablation toolsets and modalities; and (4) the advancement of ablation strategies and techniques, including ablation of complex atrial and ventricular dysrhythmias tailored to the individual patient.

  7. Scanning electron microscopy of biofilms adherent to the inner catheter surface.

    PubMed

    Pogorelov, A G; Chebotar, I V; Pogorelova, V N

    2014-09-01

    The inner surface of the drainage catheter used in surgical interventions for biliary system pathologies was examined by scanning electron microscopy. Microflora in the catheter lumen reflects etiological characteristics of the pathological process and helps to predict possible complications. The developed scanning electron microscopy imaging technique of visualization of the fi ne spatial structure of microbial biofilm formed on the catheter surface allows describing the cell pool and structure of the biofilm. PMID:25257445

  8. Cultures of Needleless Connectors Are Useful for Ruling Out Central Venous Catheter Colonization

    PubMed Central

    Pérez-Granda, María Jesús; Cruces, Raquel; Martín-Rabadán, Pablo; Bouza, Emilio

    2015-01-01

    Semiquantitative cultures of skin surrounding intravascular catheter entry sites and catheter hubs have high negative predictive values for catheter tip colonization. However, culturing samples from the inner side of the hub requires the catheter to be manipulated, thus increasing the risk of migration of microorganisms into the bloodstream. Today, hubs are closed using needleless connectors (NCs). Cultures of NCs could predict catheter colonization. Our objective was to compare the yield of NC sonicate cultures for prediction of catheter colonization with that of hub cultures. For 6 months, we prospectively collected all short-term central lines and systems removed from patients admitted to the cardiac surgery postoperative care unit, irrespective of the reason for withdrawal. Hub cultures were obtained immediately before withdrawal and were cultured using a semiquantitative method. Catheter tips were cultured using the roll-plate technique and sonication, and NCs were cultured using a semiquantitative technique after sonication. We considered NCs to be colonized when ≥1 culture was positive. We collected a total of 75 central systems. The catheter colonization rate was 10.7%. The rates for hub and NC colonization were 6.7% and 12.0%, respectively. The validity values for hubs and NCs for prediction of catheter colonization were as follows: sensitivity, 25.0% and 87.5%; specificity, 95.5% and 97.0%; positive predictive value, 40.0% and 77.8%; negative predictive value, 91.4% and 98.5%; validity index, 88.0% and 96.0%, respectively. Cultures of closed NCs can be used to rule out catheter tip colonization and are superior to hub cultures in ruling out short-term central venous catheter colonization. PMID:25878353

  9. Inducing valvular regurgitation in mice via thermal ablation of cardiac valves.

    PubMed

    Mulchrone, Ashley M; Brace, Christopher L; Hacker, Timothy A; Chesler, Naomi C

    2014-01-01

    This study presents early data in the development of a novel mouse model of heart failure utilizing thermal ablation on cardiac valves to induce valvular regurgitation. Thermal ablation of the valve was achieved through the application of radiofrequency (RF) electrical current. The objective was to apply enough energy to induce valve stiffening and retraction, which was hypothesized to produce valve insufficiency and blood regurgitation in vivo. Preliminary studies were performed to develop a workable energy delivery catheter that could be inserted through the carotid artery to the aortic valve. Catheter position between the aortic valve leaflets was verified by echocardiography. Valve function was evaluated before and after the thermal insult using Doppler measurements near the valve inflow and outflow, and early results demonstrate that the energy delivery catheter could successfully induce acute valve insufficiency. Further study is needed to refine the catheter to provide greater control over the degree of thermal damage and resulting changes in cardiac physiology.

  10. Anatomical Substrates and Ablation of Reentrant Atrial and Ventricular Tachycardias in Repaired Congenital Heart Disease

    PubMed Central

    Brouwer, Charlotte; Hazekamp, Mark G

    2016-01-01

    Advances in surgical repair techniques for various types of congenital heart disease have improved survival into adulthood over the past decades, thus exposing these patients to a high risk of atrial and ventricular arrhythmias later in life. These arrhythmias arise from complex arrhythmogenic substrates. Substrate formation may depend on both pathological myocardial remodelling and variable anatomical boundaries, determined by the type and timing of prior corrective surgery. Accordingly, arrhythmogenic substrates after repair have changed as a result of evolving surgical techniques. Radiofrequency catheter ablation offers an important therapeutic option but remains challenging due to the variable anatomy, surgically created obstacles and the complex arrhythmogenic substrates. Recent technical developments including electroanatomical mapping and image integration for delineating the anatomy facilitate complex catheter ablation procedures. The purpose of this review is to provide an update on the changing anatomical arrhythmogenic substrates and their potential impact on catheter ablation in patients with repaired congenital heart disease and tachyarrhythmias. PMID:27617095

  11. Anatomical Substrates and Ablation of Reentrant Atrial and Ventricular Tachycardias in Repaired Congenital Heart Disease.

    PubMed

    Brouwer, Charlotte; Hazekamp, Mark G; Zeppenfeld, Katja

    2016-08-01

    Advances in surgical repair techniques for various types of congenital heart disease have improved survival into adulthood over the past decades, thus exposing these patients to a high risk of atrial and ventricular arrhythmias later in life. These arrhythmias arise from complex arrhythmogenic substrates. Substrate formation may depend on both pathological myocardial remodelling and variable anatomical boundaries, determined by the type and timing of prior corrective surgery. Accordingly, arrhythmogenic substrates after repair have changed as a result of evolving surgical techniques. Radiofrequency catheter ablation offers an important therapeutic option but remains challenging due to the variable anatomy, surgically created obstacles and the complex arrhythmogenic substrates. Recent technical developments including electroanatomical mapping and image integration for delineating the anatomy facilitate complex catheter ablation procedures. The purpose of this review is to provide an update on the changing anatomical arrhythmogenic substrates and their potential impact on catheter ablation in patients with repaired congenital heart disease and tachyarrhythmias. PMID:27617095

  12. Anatomical Substrates and Ablation of Reentrant Atrial and Ventricular Tachycardias in Repaired Congenital Heart Disease

    PubMed Central

    Brouwer, Charlotte; Hazekamp, Mark G

    2016-01-01

    Advances in surgical repair techniques for various types of congenital heart disease have improved survival into adulthood over the past decades, thus exposing these patients to a high risk of atrial and ventricular arrhythmias later in life. These arrhythmias arise from complex arrhythmogenic substrates. Substrate formation may depend on both pathological myocardial remodelling and variable anatomical boundaries, determined by the type and timing of prior corrective surgery. Accordingly, arrhythmogenic substrates after repair have changed as a result of evolving surgical techniques. Radiofrequency catheter ablation offers an important therapeutic option but remains challenging due to the variable anatomy, surgically created obstacles and the complex arrhythmogenic substrates. Recent technical developments including electroanatomical mapping and image integration for delineating the anatomy facilitate complex catheter ablation procedures. The purpose of this review is to provide an update on the changing anatomical arrhythmogenic substrates and their potential impact on catheter ablation in patients with repaired congenital heart disease and tachyarrhythmias.

  13. Ultrafast laser ablation for targeted atherosclerotic plaque removal

    NASA Astrophysics Data System (ADS)

    Lanvin, Thomas; Conkey, Donald B.; Descloux, Laurent; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-07-01

    Coronary artery disease, the main cause of heart disease, develops as immune cells and lipids accumulate into plaques within the coronary arterial wall. As a plaque grows, the tissue layer (fibrous cap) separating it from the blood flow becomes thinner and increasingly susceptible to rupturing and causing a potentially lethal thrombosis. The stabilization and/or treatment of atherosclerotic plaque is required to prevent rupturing and remains an unsolved medical problem. Here we show for the first time targeted, subsurface ablation of atherosclerotic plaque using ultrafast laser pulses. Excised atherosclerotic mouse aortas were ablated with ultrafast near-infrared (NIR) laser pulses. The physical damage was characterized with histological sections of the ablated atherosclerotic arteries from six different mice. The ultrafast ablation system was integrated with optical coherence tomography (OCT) imaging for plaque-specific targeting and monitoring of the resulting ablation volume. We find that ultrafast ablation of plaque just below the surface is possible without causing damage to the fibrous cap, which indicates the potential use of ultrafast ablation for subsurface atherosclerotic plaque removal. We further demonstrate ex vivo subsurface ablation of a plaque volume through a catheter device with the high-energy ultrafast pulse delivered via hollow-core photonic crystal fiber.

  14. Development of an Electrophysiology (EP)-Enabled Intracardiac Ultrasound Catheter Integrated With NavX 3-Dimensional Electrofield Mapping for Guiding Cardiac EP Interventions

    PubMed Central

    Li, Xiao Kui; Pemberton, James; Thomenius, Kai; Dentinger, Aaron; Lowe, Robert I.; Ashraf, Muhammad; Shung, K. Kirk; Chia, Raymond; Stephens, Douglas N.; O'Donnell, Matthew; Mahajan, Aman; Balaji, Seshadri; Shivkumar, Kalyanam; Sahn, David J.

    2015-01-01

    Objective We have developed an integrated high-resolution intracardiac echocardiography (ICE) catheter for electrophysiology (EP) testing, which can be coregistered in 3-dimensional space with EP testing and ablation catheters using electrofield sensing. Methods Twelve open-chest pigs (34–55 kg) and 3 closed-chest pigs were studied. After introduction from the jugular or femoral venous locations, the 9F side-looking, highly steerable (0°–180°), 64-element array catheters could be manipulated easily throughout the right side of the heart. Multisite cardiac pacing was performed for assessing left ventricular (LV) synchrony using tissue Doppler methods. Also, in the open-chest pigs, right atrial (RA) and right ventricular (RV) ablations were performed with a separate radio frequency catheter under fluoroscopic guidance and visualized with ICE to characterize the changes. In the 3 closed-chest pigs, electrofield NavX 3-dimensional coregistration (St Jude Medical Corp, Minneapolis, MN) allowed us to test whether this additional feature could shorten the time necessary to perform 4 targeted ablations in each animal while imaging the ablation catheter and the adjacent region by ICE. Results Intracardiac anatomy, tricuspid, aortic, pulmonary, and mitral valve function, and pulmonary vein flow were all imaged reproducibly from scanning locations in the RA or RV in all animals, along with assessment of cardiac motion and the effects of multisite pacing. Three-dimensional electrofield displays detailed the spatial relationship between the ICE catheter and ablation catheters such that the time to visualize and ablate 4 sites in each of the 3 closed-chest animals was reduced. Conclusions This new technology is a first step in the integration of ICE with EP procedures. PMID:17957051

  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. Is Single-View Fluoroscopy Sufficient in Guiding Cardiac Ablation Procedures?

    PubMed Central

    Fallavollita, Pascal

    2010-01-01

    The CARTO XP ablation system provides real-time data on 3D, color-coded maps of the electrical activity of the heart; however, it is expensive and can only use a dedicated costly magnetic catheter per patient intervention. The purpose of our study is to shorten the duration of the radiofrequency ablation procedure and increase its efficacy by developing an affordable prototype catheter navigation system that simulates the CARTO system. To obtain 3D geometrical data from catheter locations inside the heart chamber, we acquired only single-view images using an Integris Allura fluoroscope and estimated the depth of the mapping electrode using pattern recognition techniques. Validation was performed in ideal and clinical conditions. For phantom experiment, when using a 7-French catheter, the average recovered depth error was 2.05 ± 1.46 mm using a single image. However, when using the 8-French catheter, the average recovered depth error was 1.54 ± 1.29 mm. In clinical experimentation, the standard error of estimate for the estimated depth was about 13.1 mm and 10.1 mm, respectively, for the posterior and lateral views. In conclusion, this paper describes our achievements and shortfalls in developing an affordable fluoroscopic navigation system to guide RF catheter ablation of cardiac arrhythmias. PMID:20368770

  17. Three-dimensional tracking of cardiac catheters using an inverse geometry x-ray fluoroscopy system

    SciTech Connect

    Speidel, Michael A.; Tomkowiak, Michael T.; Raval, Amish N.; Van Lysel, Michael S.

    2010-12-15

    Purpose: Scanning beam digital x-ray (SBDX) is an inverse geometry fluoroscopic system with high dose efficiency and the ability to perform continuous real-time tomosynthesis at multiple planes. This study describes a tomosynthesis-based method for 3D tracking of high-contrast objects and present the first experimental investigation of cardiac catheter tracking using a prototype SBDX system. Methods: The 3D tracking algorithm utilizes the stack of regularly spaced tomosynthetic planes that are generated by SBDX after each frame period (15 frames/s). Gradient-filtered versions of the image planes are generated, the filtered images are segmented into object regions, and then a 3D coordinate is calculated for each object region. Two phantom studies of tracking performance were conducted. In the first study, an ablation catheter in a chest phantom was imaged as it was pulled along a 3D trajectory defined by a catheter sheath (10, 25, and 50 mm/s pullback speeds). SBDX tip tracking coordinates were compared to the 3D trajectory of the sheath as determined from a CT scan of the phantom after the registration of the SBDX and CT coordinate systems. In the second study, frame-to-frame tracking precision was measured for six different catheter configurations as a function of image noise level (662-7625 photons/mm{sup 2} mean detected x-ray fluence at isocenter). Results: During catheter pullbacks, the 3D distance between the tracked catheter tip and the sheath centerline was 1.0{+-}0.8 mm (mean {+-}one standard deviation). The electrode to centerline distances were comparable to the diameter of the catheter tip (2.3 mm), the confining sheath (4 mm outside diameter), and the estimated SBDX-to-CT registration error ({+-}0.7 mm). The tip position was localized for all 332 image frames analyzed and 83% of tracked positions were inside the 3D sheath volume derived from CT. The pullback speeds derived from the catheter trajectories were within 5% of the programed pullback speeds

  18. MRI-guided prostate focal laser ablation therapy using a mechatronic needle guidance system

    NASA Astrophysics Data System (ADS)

    Cepek, Jeremy; Lindner, Uri; Ghai, Sangeet; Davidson, Sean R. H.; Trachtenberg, John; Fenster, Aaron

    2014-03-01

    Focal therapy of localized prostate cancer is receiving increased attention due to its potential for providing effective cancer control in select patients with minimal treatment-related side effects. Magnetic resonance imaging (MRI)-guided focal laser ablation (FLA) therapy is an attractive modality for such an approach. In FLA therapy, accurate placement of laser fibers is critical to ensuring that the full target volume is ablated. In practice, error in needle placement is invariably present due to pre- to intra-procedure image registration error, needle deflection, prostate motion, and variability in interventionalist skill. In addition, some of these sources of error are difficult to control, since the available workspace and patient positions are restricted within a clinical MRI bore. In an attempt to take full advantage of the utility of intraprocedure MRI, while minimizing error in needle placement, we developed an MRI-compatible mechatronic system for guiding needles to the prostate for FLA therapy. The system has been used to place interstitial catheters for MRI-guided FLA therapy in eight subjects in an ongoing Phase I/II clinical trial. Data from these cases has provided quantification of the level of uncertainty in needle placement error. To relate needle placement error to clinical outcome, we developed a model for predicting the probability of achieving complete focal target ablation for a family of parameterized treatment plans. Results from this work have enabled the specification of evidence-based selection criteria for the maximum target size that can be confidently ablated using this technique, and quantify the benefit that may be gained with improvements in needle placement accuracy.

  19. Fragmentation and ablation during entry

    SciTech Connect

    Canavan, G.H.

    1997-09-01

    This note discusses objects that both fragment and ablate during entry, using the results of previous reports to describe the velocity, pressure, and fragmentation of entering objects. It shows that the mechanisms used there to describe the breakup of non-ablating objects during deceleration remain valid for most ablating objects. It treats coupled fragmentation and ablation during entry, building on earlier models that separately discuss the entry of objects that are hard, whose high heat of ablation permits little erosion, and those who are strong whose strength prevents fragmentation, which are discussed in ``Radiation from Hard Objects,`` ``Deceleration and Radiation of Strong, Hard, Asteroids During Atmospheric Impact,`` and ``Meteor Signature Interpretation.`` This note provides a more detailed treatment of the further breakup and separation of fragments during descent. It replaces the constraint on mass per unit area used earlier to determine the altitude and magnitude of peak power radiation with a detailed analytic solution of deceleration. Model predictions are shown to be in agreement with the key features of numerical calculations of deceleration. The model equations are solved for the altitudes of maximum radiation, which agree with numerical integrations. The model is inverted analytically to infer object size and speed from measurements of peak power and altitude to provide a complete model for the approximate inversion of meteor data.

  20. 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 ...

  1. Peripherally inserted central catheter - insertion

    MedlinePlus

    PICC - insertion ... A PICC is a long, thin tube (called a catheter) that goes into your body through a vein in ... into a large vein near your heart. The PICC helps carry nutrients and medicines into your body. ...

  2. Peripherally inserted central catheter - flushing

    MedlinePlus

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

  3. Hemodialysis catheter exit site care.

    PubMed

    Astle, Colleen M

    2007-01-01

    Tunneled, cuffed central venous catheters are used extensively throughout the hemodialysis patient population as a permanent arterio-venous access. One of the major complications associated with these devices is infection. The strategies aimed at reducing catheter-related infection include nurse-patient ratio, use of barrier precautions, hand washing, ointments, dressings, and skin antiseptics. The intent of this paper is to examine the types of skin antiseptics and compare their effectiveness.

  4. Organized Atrial Tachycardias after Atrial Fibrillation Ablation

    PubMed Central

    Castrejón-Castrejón, Sergio; Ortega, Marta; Pérez-Silva, Armando; Doiny, David; Estrada, Alejandro; Filgueiras, David; López-Sendón, José L.; Merino, José L.

    2011-01-01

    The efficacy of catheter-based ablation techniques to treat atrial fibrillation is limited not only by recurrences of this arrhythmia but also, and not less importantly, by new-onset organized atrial tachycardias. The incidence of such tachycardias depends on the type and duration of the baseline atrial fibrillation and specially on the ablation technique which was used during the index procedure. It has been repeatedly reported that the more extensive the left atrial surface ablated, the higher the incidence of organized atrial tachycardias. The exact origin of the pathologic substrate of these trachycardias is not fully understood and may result from the interaction between preexistent regions with abnormal electrical properties and the new ones resultant from radiofrequency delivery. From a clinical point of view these atrial tachycardias tend to remit after a variable time but in some cases are responsible for significant symptoms. A precise knowledge of the most frequent types of these arrhythmias, of their mechanisms and components is necessary for a thorough electrophysiologic characterization if a new ablation procedure is required. PMID:21941669

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Effectiveness of Integrating Delayed Computed Tomography Angiography Imaging for Left Atrial Appendage Thrombus Exclusion into the Care of Patients Undergoing Ablation of Atrial Fibrillation

    PubMed Central

    Bilchick, Kenneth C.; Mealor, Augustus; Gonzalez, Jorge; Norton, Patrick; Zhuo, David; Mason, Pamela; Ferguson, John D.; Malhotra, Rohit; Mangrum, J. Michael; Darby, Andrew E.; DiMarco, John; Hagspiel, Klaus; Dent, John; Kramer, Christopher M.; Stukenborg, George J.; Salerno, Michael

    2015-01-01

    Background Computed tomography angiography (CTA) can identify and rule out left atrial appendage (LAA) thrombus when delayed imaging is also performed. Objective In patients referred for CTA for pulmonary vein anatomy prior to ablation of atrial fibrillation or atypical left atrial flutter (AF), we sought to determine the effectiveness of a novel clinical protocol for integrating results of CTA delayed imaging of the LAA into pre-procedure care. Methods After making delayed imaging of the LAA part of our routine pre-ablation CTA protocol, we integrated early reporting of pre-ablation CTA LAA imaging results into clinical practice as part of a formal protocol in June 2013. We then analyzed the effectiveness of this protocol by evaluating 320 AF ablation patients with CTA imaging during 2012–2014. Results Among CTA patients with delayed LAA imaging, the sensitivity and negative predictive values for LAA thrombus with intracardiac echocardiography (ICE) or transesophageal echocardiograms (TEEs) as the reference standard were both 100%. ICE during ablation confirmed absence of thrombus in patients with a negative CTA or negative TEE. No patients with either a negative CTA or an equivocal CTA combined with a negative TEE had strokes or transient ischemic attacks. Overall, the need for TEEs decreased from 57.5% to 24.0% during the 3-year period as a result of the CTA protocol. Conclusions Clinical integration of CTA with delayed LAA imaging into the care of patients having catheter ablation of AF is feasible, safe, and effective. Such a protocol could be applied broadly to improve patient care. PMID:26341605

  11. 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

  12. Saphenous Venous Ablation with Hot Contrast in a Canine Model

    SciTech Connect

    Prasad, Amit Qian Zhong; Kirsch, David; Eissa, Marna; Narra, Pavan; Lopera, Jorge; Espinoza, Carmen G.; Castaneda, Wifrido

    2008-01-15

    Purpose. To determine the feasibility, efficacy, and safety of thermal ablation of the saphenous vein with hot contrast medium. Methods. Twelve saphenous veins of 6 dogs were percutaneously ablated with hot contrast medium. In all animals, ablation was performed in the vein of one leg, followed by ablation in the contralateral side 1 month later. An occlusion balloon catheter was placed in the infragenicular segment of the saphenous vein via a jugular access to prevent unwanted thermal effects on the non-target segment of the saphenous vein. After inflation of the balloon, 10 ml of hot contrast medium was injected under fluoroscopic control through a sheath placed in the saphenous vein above the ankle. A second 10 ml injection of hot contrast medium was made after 5 min in each vessel. Venographic follow-up of the ablated veins was performed at 1 month (n = 12) and 2 months (n = 6). Results. Follow-up venograms showed that all ablated venous segments were occluded at 1 month. In 6 veins which were followed up to 2 months, 4 (66%) remained occluded, 1 (16%) was partially patent, and the remaining vein (16%) was completely patent. In these latter 2 cases, an inadequate amount of hot contrast was delivered to the lumen due to a closed balloon catheter downstream which did not allow contrast to displace blood within the vessel. Discussion. Hot contrast medium thermal ablation of the saphenous vein appears feasible, safe, and effective in the canine model, provided an adequate amount of embolization agent is used.

  13. 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.

  14. Thermal Ablation Modeling for Silicate Materials

    NASA Technical Reports Server (NTRS)

    Chen, Yih-Kanq

    2016-01-01

    A general thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in the ablation simulation of the meteoroid and the glassy ablator for spacecraft Thermal Protection Systems. Time-dependent axisymmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. The predicted mass loss rates will be compared with available data for model validation, and parametric studies will also be performed for meteoroid earth entry conditions.

  15. Heparin Leakage in Central Venous Catheters by Hemodynamic Transport

    NASA Astrophysics Data System (ADS)

    Barbour, Michael; McGah, Patrick; Gow, Kenneth; Aliseda, Alberto

    2014-11-01

    Central venous catheters (CVCs), placed in the superior vena cava for hemodialysis, are routinely filled with heparin, an anticoagulant, while not in use to maintain patency and prevent thrombus formation at the catheter tip. However, the heparin-lock procedure places the patient at risk for systemic bleeding incidences, as heparin is known to leak into the blood stream. We propose that the driving mechanism behind heparin leakage is advective-diffusive transport due to the pulsatile blood flow surrounding the catheter tip. This novel hypothesis is based on Planar Laser Induced Fluorescence (PLIF) measurements of heparin transport from a CVC placed inside an in vitro pulsatile flow loop and validated with CFD simulations. The results show an initial, fast (<10s), advection-dominated phase that rapidly depletes the concentration of heparin at the CVC tip, followed by a slow, diffusion-limited phase inside the catheter lumen, where concentration is still high, that is insufficient at replenishing the lost heparin at the tip. These results, which estimate leakage rates consistent with published in vivo data, predict that the concentration of heparin at the catheter tip is effectively zero for the majority of the interdialytic phase, rendering the heparin lock ineffective.

  16. Urinary Retention: Catheter Drainage Bag or Catheter Valve?

    PubMed Central

    Virdi, Gurnam; Hendry, David

    2016-01-01

    The management of patients with intractable urinary incontinence presents as a challenging priority in the ageing population. To preserve the antibacterial mechanisms of the bladder, a urine collection that enables the bladder to fill and empty regularly and completely, should be used. This mimics the action of the healthy bladder. We compared the success rates of two widely used urinary-collection systems (catheter with drainage bag or a catheter valve) at our institution for those patients undergoing a trial of void. PMID:26989368

  17. Laser ablation of blepharopigmentation

    SciTech Connect

    Tanenbaum, M.; Karas, S.; McCord, C.D. Jr. )

    1988-01-01

    This article discusses laser ablation of blepharopigmentation in four stages: first, experimentally, where pigment vaporization is readily achieved with the argon blue-green laser; second, in the rabbit animal model, where eyelid blepharopigmentation markings are ablated with the laser; third, in human subjects, where the argon blue-green laser is effective in the ablation of implanted eyelid pigment; and fourth, in a case report, where, in a patient with improper pigment placement in the eyelid, the laser is used to safely and effectively ablate the undesired pigment markings. This article describes in detail the new technique of laser ablation of blepharopigmentation. Potential complications associated with the technique are discussed.

  18. Transcatheter patent foramen ovale closure and radiofrequency ablation of right atrial tachycardia.

    PubMed

    Manola, Šime; Bernat, Robert; Pavlović, Nikola; Radeljić, Vjekoslav; Bulj, Nikola; Trbušić, Matias

    2014-12-01

    Patent foramen ovale (PFO) can be found in approximately 25% of adult population. Transcatheter closure of PFO is a potential option in selected patients with PFO. We report a case of a female patient that underwent mapping and catheter ablation of atrial tachycardia and PFO closure in the same procedure.

  19. Thermistor guided radiofrequency ablation of atrial insertion sites in patients with accessory pathways.

    PubMed

    Tracy, C M; Moore, H J; Solomon, A J; Rodak, D J; Fletcher, R D

    1995-11-01

    Radiofrequency ablation has gained acceptance in the treatment of patients with symptomatic Wolff-Parkinson-White syndrome. The purpose of this study was to characterize the relation between temperature and other electroconductive parameters in patients undergoing atrial insertion accessory pathway ablation utilizing a thermistor equipped catheter. The mean temperature and power at sites of atrial insertion ablation are lower than has been previously associated with creation of radiofrequency lesions in the ventricle. While high cavitary blood flow in the atrium may result in cooling, the thinner atrial tissue may require less energy to achieve adequate heating than ventricular myocardium.

  20. Laser fiber migration into the pelvic cavity: A rare complication of endovenous laser ablation.

    PubMed

    Lun, Yu; Shen, Shikai; Wu, Xiaoyu; Jiang, Han; Xin, Shijie; Zhang, Jian

    2015-10-01

    Endovenous laser ablation is an established alternative to surgery with stripping for the treatment of varicose veins. Ecchymoses and pain are frequently reported side effects of endovenous laser ablation. Device-related complications are rare but serious. We describe here an exceptional complication, necessitating an additional surgical procedure to remove a segment of laser fiber that had migrated into the pelvic cavity. Fortunately, severe damage had not occurred. This case highlights the importance of checking the completeness of the guidewire, catheter, and laser fiber after endovenous laser ablation.

  1. 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.

  2. An in vivo comparison of radiofrequency cardiac lesions formed by standard and magnetically steered 4 mm tip catheters

    PubMed Central

    Thornton, A.S.; De Castro, C.A. Brito; van Deel, E.; van Beusekom, H.M.M.; Jordaens, L.

    2010-01-01

    Background. In vivo comparison of cardiac radiofrequency ablation lesions between standard and magnetically steered 4 mm tip catheters has never been reported. Methods. High and low right atrium (RA) free wall, isthmus, right ventricle (RV) free wall and outflow tract lesions were studied macroscopically and microscopically five days after lesion formation in seven pigs. Shape, size, thrombus formation, and ablation parameters were compared. The effect of minimal, medium and high wall contact was assessed by a contact measurement utility for magnetic catheters. Results. All 14 RA free wall lesions were transmural with a similar epicardial and endocardial surface area. In the RV, the epicardial area usually appeared to be smaller than the endocardial area with standard catheters. Isthmus lesions were difficult to assess transmurality. There was no difference in endocardial area: standard 39 mm2 (range 16 to 82 mm2) vs. magnetic 36 mm2 (range 23 to 111 mm2). If the catheter tip was perpendicular to the tissue, magnetic lesions were more often round or oval, while standard lesions were more often elongated (p<0.05). When the catheter tip was parallel to tissue, lesions always tended to be elongated. Microscopic characteristics were similar. The contact utility was not useful. Average impedance (p<0.0001) and energy delivered (p<0.05) were less with magnetic catheters. Conclusion. Lesions from magnetically steered catheters are transmural of similar size, but with less variability than standard catheter lesions when the tip is perpendicular to the tissue. Magnetic lesions are associated with lower impedance and energy delivery. This suggests a more stable tip-to-tissue contact. (Neth Heart J 2010;18:66–71.) PMID:20200611

  3. Optical modeling of laser ablated microstructures

    NASA Astrophysics Data System (ADS)

    Gower, M. C.; Davies, E.; Holmes, A. S.

    2012-11-01

    From only an a priori knowledge of the optical parameters of a laser beam, the delivery system together with a substrate's material properties, a ray-tracing model capable of predicting the 3-D topology of micro/nanostructures machined by pulsed laser ablation has been developed. The model includes secondary illumination effects produced by the microstructure created by successive pulses (wall reflections, refraction, wave guiding, shadowing, etc.) as well as the complete optical properties of the beam delivery system. We have used material ablation by pulsed excimer lasers and associated beam delivery systems to demonstrate some of the capabilities of the model. Good agreement is obtained between computations and experimental results in terms of the predicted ablation depth per pulse and the wall taper angle of channels and holes. The model can predict ablated profiles of holes and indicate the most efficient drilling strategy in terms of material removal rates. The model also shows diffraction effects are not required to explain the tapering vertical walls observed when ablating microstructures. Finally, the model has been used to demonstrate aberrations in an optical imaging system limiting the creation of submicron features in an ablated microstructure. Provided photons are absorbed linearly in a substrate according to Beer's law with negligible thermal diffusion effects, the model is equally applicable to using other types of pulsed laser sources and systems with imaged or focused beams.

  4. [Pulmonary vein ablation in atrial fibrillation. Initial experience].

    PubMed

    Velarde, José Luis; Martellotto, Ricardo; Scanavacca, Mauricio; Arévalo, Aldo; Colque, Roberto; Jiménez, Marcelo

    2002-05-01

    Despite the progress in the knowledge of the pathophysiology of the atrial fibrillation (AF), the pharmacologic and non pharmacologic approach to prevent and control this arrhythmia has been shown to be discouraging. In the past few years a new type of AF has been described, of which the focal mechanism -especially bound to the pulmonary veins- allows ablation treatment through the radiofrequency (RF) with a catheter. We present our initial experience with this type of method, in two young patients who suffered from multiples episodes of AF and resistance to the conventional treatment. In both patients the RF ablation was done in the left superior pulmonary vein. One of them received an ablation in only one focus, and the other needed a veno-atrial disconnection through the elimination of the pulmonary venous potential from this vein. After three month of follow-up, patients remain asymptomatic with no relapse. PMID:12015937

  5. 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...

  6. 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...

  7. Ventricular dysfunction following direct-current shock atrioventricular junction ablation.

    PubMed

    Warren, R J; Vohra, J K; Chan, W; Lichtenstein, M; Mond, H G; Hunt, D

    1991-02-01

    Catheter-induced His bundle ablation for refractory supraventricular arrhythmias is most commonly performed with direct-current shock energy of 200-300 joules. The high energy pulse delivered by direct-current shock produces a lesion in the atrioventricular node by fulguration, with the residual energy being dissipated as a pressure wave. The effect of direct-current shock His bundle ablation on global and regional ventricular function was assessed in 14 consecutive patients by radionuclide ventriculography performed before and after ablation and again three months later. All studies were performed with ventricular pacing at 110 bpm. Global left ventricular ejection fraction was found to be significantly reduced at the three month study (0.43 +/- 0.03 vs 0.50 +/- 0.03, pre ablation, p = 0.02). A significant reduction in wall-motion score was also seen in six of the seven patients who had normal wall motion in pacing rhythm prior to ablation. Deterioration was mainly seen at the left and right ventricular apices. The observed reduction in ventricular function that follows direct-current shock His bundle ablation may result from myocardial damage from electro-coagulation or from barotrauma and supports continued investigation into alternative, less traumatic energy sources for the procedure. PMID:2036072

  8. Ventricular dysfunction following direct-current shock atrioventricular junction ablation.

    PubMed

    Warren, R J; Vohra, J K; Chan, W; Lichtenstein, M; Mond, H G; Hunt, D

    1991-02-01

    Catheter-induced His bundle ablation for refractory supraventricular arrhythmias is most commonly performed with direct-current shock energy of 200-300 joules. The high energy pulse delivered by direct-current shock produces a lesion in the atrioventricular node by fulguration, with the residual energy being dissipated as a pressure wave. The effect of direct-current shock His bundle ablation on global and regional ventricular function was assessed in 14 consecutive patients by radionuclide ventriculography performed before and after ablation and again three months later. All studies were performed with ventricular pacing at 110 bpm. Global left ventricular ejection fraction was found to be significantly reduced at the three month study (0.43 +/- 0.03 vs 0.50 +/- 0.03, pre ablation, p = 0.02). A significant reduction in wall-motion score was also seen in six of the seven patients who had normal wall motion in pacing rhythm prior to ablation. Deterioration was mainly seen at the left and right ventricular apices. The observed reduction in ventricular function that follows direct-current shock His bundle ablation may result from myocardial damage from electro-coagulation or from barotrauma and supports continued investigation into alternative, less traumatic energy sources for the procedure.

  9. Temperature-controlled cooled-tip radiofrequency linear ablation of the atria guided by a realtime position management system.

    PubMed

    Watanabe, Ichiro; Min, Nuo; Okumura, Yasuo; Ohkubo, Kimie; Kofune, Masayoshi; Ashino, Sonoko; Nagashima, Koichi; Nakai, Toshiko; Kasamaki, Yuji; Hirayama, Atsushi

    2011-01-01

    Due to the difficulty in producing a transmural linear lesion and the possibility of complications such as thrombus formation leading to thromboembolism, the catheter-based maze procedure remains problematic. We tested, in pigs, the possibility of using a temperature-controlled cooled-tip radiofrequency (RF) ablation system together with a realtime position management (RPM) system to create a transmural linear lesion uncomplicated by thrombus formation.Nine pigs underwent insertion of two electrode catheters (each with two ultrasound electrodes), one into the coronary sinus (CS) and one into the right ventricular apex (references for ultrasound-based non-fluoroscopic three-dimensional mapping). A cooled-tip catheter (with two ultrasound electrodes) was introduced into the right atrium. Linear right atrial ablation was performed with a custom radiofrequency (RF) generator. The catheter was perfused with 0.66 mL/second of saline. RF was delivered for 60 seconds at a target temperature of 40°C. A linear ablation line was created between the superior vena cava and inferior vena cava. Three-dimensional isochronal maps were created during CS pacing before and after ablation. In 4 of the 9 pigs, a transmural linear ablation line was confirmed by three-dimensional mapping and postmortem macroscopic examination. No endocardial thrombus formation was noted. Temperature-controlled cooled-tip RF linear ablation guided by an RPM system appears to have potential for creating linear lesions in the atria. Further studies are needed to determine whether such an ablation technique and the parameters used will facilitate successful completion of the catheter-based maze procedure.

  10. 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.

  11. KTP-532 laser ablation of urethral strictures

    NASA Astrophysics Data System (ADS)

    Malloy, Terrence R.

    1991-07-01

    In 1988, the KTP-532 laser was used to ablate a series of benign urethral strictures. Rather than using a single incision, as in urethrotomy, strictures were treated with a 360$DEG contact photoradiation. Thirty-one males, average age 53.2 years, received 37 treatments. Six patients underwent a second laser treatment. Stricture etiology was commonly iatrogenic (32%), traumatic (16%), and post-gonococcal (10%). Stricture location included mainly bulbar (49%), membranous (20%), and penile (12%) areas. The surgical technique consisted of a circumferential ablation followed by foley catheter placement (mean 10 days). Follow-up on 29 of 31 patients ranged from 1 to 16 months (mean 9.7) Complete success occurred in 17 patients (59%) who had no further symptoms or instrumentation. Partial success was seen in 6 patients (20.5%) with symptoms but no stricture recurrence. Six patients (20.5%) failed therapy requiring additional surgery or regular dilatations. No complications were encountered. Although longer assessment is required, KTP-532 laser ablation of urethral strictures appears efficacious.

  12. Transurethral radio frequency ablation of the prostate

    NASA Astrophysics Data System (ADS)

    Kabalin, John N.

    1996-05-01

    Since 1993, radiofrequency ablation of the prostate has been studied as a potential treatment for symptomatic bladder outlet obstruction due to benign prostatic hyperplasia. Two transurethral radiofrequency delivery systems have been developed to the point of undergoing initial human clinical trials. The TUNATM system involves focal interstitial radiofrequency energy application, while the TURAPYTM system involves a circumferential application of radiofrequency energy to the prostatic urethra via a simple delivery catheter. Experimental studies in animal models and human prostate tissue have demonstrated the nature of radiofrequency induced tissue heating and thermal injury. Observed thermal effects are relatively focused, with steep temperature gradients occurring over a few millimeters from the radiofrequency emission source. This allows precise and focused tissue treatment with little or no danger of injury to surrounding structures. Early human clinical experience in the treatment of benign prostatic hyperplasia has demonstrated efficacy in the relief of voiding symptoms and safety and minimal morbidity associated with this technology. The existing operative approaches are relatively simple. Ongoing development of more versatile delivery systems for radiofrequency ablation of the prostate is expected. Results from larger clinical trials with longer term followup will eventually allow adequate assessment of the role of radiofrequency ablation in the surgical management of benign prostatic hyperplasia.

  13. The serum matrix metalloproteinase-9 level is an independent predictor of recurrence after ablation of persistent atrial fibrillation

    PubMed Central

    Wu, Gang; Wang, Shun; Cheng, Mian; Peng, Bin; Liang, Jingjun; Huang, He; Jiang, Xuejun; Zhang, Lizhi; Yang, Bo; Cha, Yongmei; Jiang, Hong; Huang, Congxin

    2016-01-01

    OBJECTIVES: This study investigated whether the serum matrix metalloproteinase-9 level is an independent predictor of recurrence after catheter ablation for persistent atrial fibrillation. METHODS: Fifty-eight consecutive patients with persistent atrial fibrillation were enrolled and underwent catheter ablation. The serum matrix metalloproteinase-9 level was detected before ablation and its relationship with recurrent arrhythmia was analyzed at the end of the follow-up. RESULTS: After a mean follow-up of 12.1±7.2 months, 21 (36.2%) patients had a recurrence of their arrhythmia after catheter ablation. At baseline, the matrix metalloproteinase-9 level was higher in the patients with recurrence than in the non-recurrent group (305.77±88.90 vs 234.41±93.36 ng/ml, respectively, p=0.006). A multivariate analysis showed that the matrix metalloproteinase-9 level was an independent predictor of arrhythmia recurrence, as was a history of atrial fibrillation and the diameter of the left atrium. CONCLUSION: The serum matrix metalloproteinase-9 level is an independent predictor of recurrent arrhythmia after catheter ablation in patients with persistent atrial fibrillation. PMID:27276393

  14. Percutaneously inserted central catheter - infants

    MedlinePlus

    ... the PICC through the needle into a larger (central) vein, putting its tip near (but not in) the heart. Take an x-ray to place the needle. Remove the needle after the catheter is placed. WHAT ARE THE RISKS OF HAVING ...

  15. Aging of silastic peritoneal catheters.

    PubMed

    Poisetti, P; Bergonzi, G; Ballocchi, S; Fontana, F; Scarpioni, L

    1991-12-01

    Increasing the survival of patients on CAPD is related to the long-term reliability of the peritoneal access. Six silicone Tenckhoff catheters (with strip or diffuse barium sulphate inclusion) removed after 39-69 months because of the appearance of external segment fissures, were analysed by scanning electron microscopy (SEM) and infra-red spectroscopy with attenuated total refractance (ATR). The extracorporeal portion of the catheters showed (by ATR) a more prominent oxidation peak on the external than the internal surface; SEM showed marks and cracks on the external surface and exfoliation and flattening of the silastic reticle on the intraluminal surface. No evidence of oxidation was found in the intra-abdominal portion of the catheters but biofilm was found. We suggest that barium sulphate may render the silastic brittle and physiological and environmental long-term factors (such as uv-rays, temperature, sweat and disinfectants) could cause oxidation and loss of physico-chemical properties, with critical aging of the silastic and loss of catheter resistance to mechanical injury. PMID:1783450

  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. 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

  18. Ablation of atrial flutter in a patient with a tricuspid valve replacement after endocarditis.

    PubMed

    Nordbeck, Peter; Bauer, Wolfgang R; Ritter, Oliver

    2009-09-01

    Myocardial scars from heart surgery are a source of tachycardia, eventually causing late morbidity and sudden death. In general, catheter ablation has been shown to be an effective therapy for various rhythm disorders, but it has been rarely described after atrioventricular valve replacement. We report on a 45-year-old man who developed atrial flutter after implantation of a tricuspid valve bioprosthesis. An electrophysiological investigation revealed typical type-I counterclockwise atrial flutter that was successfully terminated by catheter ablation. A sinus rhythm was restored and remained stable during the course of treatment; the valvular function was not diminished. It is demonstrated that safe mapping and ablation of typical atrial flutter is possible after a tricuspid valve replacement.

  19. Renal Ablation Update

    PubMed Central

    Khiatani, Vishal; Dixon, Robert G.

    2014-01-01

    Thermal ablative technologies have evolved considerably in the recent past and are now an important component of current clinical guidelines for the treatment of small renal masses. Both radiofrequency ablation and cryoablation have intermediate-term oncologic control that rivals surgical options, with favorable complication profiles. Studies comparing cryoablation and radiofrequency ablation show no significant difference in oncologic control or complication profile between the two modalities. Early data from small series with microwave ablation have shown similar promising results. Newer technologies including irreversible electroporation and high-intensity–focused ultrasound have theoretical advantages, but will require further research before becoming a routine part of the ablation armamentarium. The purpose of this review article is to discuss the current ablative technologies available, briefly review their mechanisms of action, discuss technical aspects of each, and provide current data supporting their use. PMID:25049445

  20. 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.

  1. 2D/3D registration using only single-view fluoroscopy to guide cardiac ablation procedures: a feasibility study

    NASA Astrophysics Data System (ADS)

    Fallavollita, Pascal

    2010-02-01

    The CARTO XP is an electroanatomical cardiac mapping system that provides 3D color-coded maps of the electrical activity of the heart, however it is expensive and it can only use a single costly magnetic catheter for each patient intervention. Aim: To develop an affordable fluoroscopic navigation system that could shorten the duration of RF ablation procedures and increase its efficacy. Methodology: A 4-step filtering technique was implemented in order to project the tip electrode of an ablation catheter visible in single-view C-arm images in order to calculate its width. The width is directly proportional to the depth of the catheter. Results: For phantom experimentation, when displacing a 7- French catheter at 1cm intervals away from an X-ray source, the recovered depth using a single image was 2.05 +/- 1.47 mm, whereas depth errors improved to 1.55 +/- 1.30 mm when using an 8-French catheter. In clinic experimentation, twenty posterior and left lateral images of a catheter inside the left ventricle of a mongrel dog were acquired. The standard error of estimate for the recovered depth of the tip-electrode of the mapping catheter was 13.1 mm and 10.1 mm respectively for the posterior and lateral views. Conclusions: A filtering implementation using single-view C-arm images showed that it was possible to recover depth in phantom study and proved adequate in clinical experimentation based on isochronal map fusion results.

  2. Catheter related infections in Damas Hospital.

    PubMed

    Lugo, L J; Zapata, N J; Ramírez Ronda, C H

    1994-01-01

    The purpose of this study is to investigate the extent of catheter-related infections in our Institution. We examined retrospectively 89 medical records of patients in whom an intravascular catheter tip culture were obtained during January through December 1991. Forty-seven catheter related infections were identified in 43 patients. There were 33 multiple lumen infected catheters and 14 single lumen. Catheters for hemodialysis were infected in 38.3% of the patients. Twenty catheters were inserted into the subclavian vein. Fifty percent of the reinserted catheters were placed in the same site, of which 28.6% became infected. Staphylococcus epidermis was isolated in 28.1% of the patients, while in 50% of the patients with Staphylococcus aureus, bacteremia was identified. Staphylococci and Enterococci were more sensitive to Vancomycin than to any other antibiotic. PMID:7916776

  3. Catheter-Based Ultrasound for 3D Control of Thermal Therapy

    NASA Astrophysics Data System (ADS)

    Diederich, Chris; Chen, Xin; Wootton, Jeffery; Juang, Titania; Nau, Will H.; Kinsey, Adam; Hsu, I.-Chow; Rieke, Viola; Pauly, Kim Butts; Sommer, Graham; Bouley, Donna

    2009-04-01

    Catheter-based ultrasound applicators have been investigated for delivering hyperthermia and thermal ablation for the treatment of cancer and benign diseases. Technology includes an intrauterine applicator integrated with an HDR ring applicator, interstitial applicators for hyperthermia delivery during brachytherapy, interstitial applicators for tumor ablation, and transurethral devices for conformal prostate ablation. Arrays of multiple sectored tubular transducers have been fabricated for interstitial and intrauterine hyperthermia applicators. High-power interstitial versions have been evaluated for percutaneous implantation with directional or dynamic angular control of thermal ablation. Transurethral applicators include curvilinear transducers with rotational sweeping of narrow heating patterns, and multi-sectored tubular devices capable of dynamic angular control without applicator movement. Performance was evaluated in phantom, excised tissue, in vivo experiments in canine prostate under MR temperature monitoring, clinical hyperthermia, and 3D-biothermal simulations with patient anatomy. Interstitial and intrauterine devices can tailor hyperthermia to large treatment volumes, with multisectored control useful to limit exposure to rectum and bladder. Curvilinear transurethral devices with sequential rotation produce target conforming coagulation zones that can cover either the whole gland or defined focal regions. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the prostate without applicator manipulation. High-power interstitial implants with directional devices can be used to effectively ablate defined target regions while avoiding sensitive tissues. MR temperature monitoring can effectively define the extent of thermal damage and provided a means for real-time control of the applicators. In summary, these catheter-based ultrasound devices allow for dynamic control of heating profiles

  4. Method for selective thermal ablation

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James (Inventor); Ngo, Phong (Inventor); Raffoul, George W. (Inventor)

    2003-01-01

    A method, simulation, and apparatus are provided that are highly suitable for treatment of benign prostatic hyperplasia (BPH). A catheter is disclosed that includes a small diameter disk loaded monopole antenna surrounded by fusion material having a high heat of fusion and a melting point preferably at or near body temperature. Microwaves from the antenna heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. The fusion material keeps the urethra cool by means of the heat of fusion of the fusion material. This prevents damage to the urethra while the prostatic tissue is necrosed. A computer simulation is provided that can be used to predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of the catheter and method of applying microwave energy a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  5. Method for Selective Thermal Ablation

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James (Inventor); Ngo, Phong (Inventor); Raffoul, George W. (Inventor)

    2003-01-01

    A method, simulation, and apparatus are provided that are highly suitable for treatment of benign prostatic hyperplasia (BPH). A catheter is disclosed that includes a small diameter disk loaded monopole antenna surrounded by fusion material having a high heat of fusion and a melting point preferably at or near body temperature. Microwaves from the antenna heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. The fusion material keeps the urethra cool by means of the heat of fusion of the fusion material. This prevents damage to the urethra while the prostatic tissue is necrosed. A computer simulation is provided that can be used to predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of the catheter and method of applying microwave energy a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  6. 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.

  7. [Clinical analysis of pediatric shunt catheter fracture].

    PubMed

    Morishita, Akitsugu; Nagashima, Tatsuya; Kurata, Hiromitsu; Eguchi, Takahiro; Tamaki, Norihiko

    2002-08-01

    Between 1985 and 1998, 415 shunt dysfunctions occurred at Kobe Children's Hospital. The main reasons for shunt revision were obstruction of the catheter, shunt infection, and shunt disconnection. This report presents an analysis of 35 patients (36 cases) who underwent a ventriculoperitoneal (VP) shunt revision because of shunt catheter fracture. All patients were less than 18 years old. We researched their age at the time of revision, site of disruption, postoperative period, shunt system, clinical symptoms, and other factors. The mechanical aspects of shunt catheter fracture are also discussed in this report. The peak time of shunt catheter fracture was the time when children were growing up and were entering elementary school. In other words, when their height was increasing rapidly. At that time, the distal catheter is subjected to traction between the valve and the abdomen at the site of insertion in either the upper or lower direction. However, physical examination of the shunt catheter showed normal range. Additional contributory factors were chronic stimulation at the occipital bone, clavium bone, and costal arch, while movement of the neck and body rotation also caused shunt catheter fracture. These factors all originated from shearing strain at the shunt catheter. We look forward to the introduction of a stronger shunt catheter, because surgical repair time must be minimized to protect the child's mental development. In addition, shearing strain at the shunt catheter needs special attention.

  8. Sprayable lightweight ablative coating

    NASA Technical Reports Server (NTRS)

    Simpson, William G. (Inventor); Sharpe, Max H. (Inventor); Hill, William E. (Inventor)

    1991-01-01

    An improved lightweight, ablative coating is disclosed that may be spray applied and cured without the development of appreciable shrinkage cracks. The ablative mixture consists essentially of phenolic microballoons, hollow glass spheres, glass fibers, ground cork, a flexibilized resin binder, and an activated colloidal clay.

  9. Hemodynamics of Central Venous Catheters: experiments and simulations

    NASA Astrophysics Data System (ADS)

    Barbour, Michael; McGah, Patrick; Clark, Alicia; Ng, Chin Hei; Gow, Kenneth; Aliseda, Alberto

    2013-11-01

    Central venous catheters (CVC) are used to provide vascular access during hemodialysis in patients with end-stage kidney disease. Despite several advantages and widespread use, CVCs have a high incidence rate of clot formation during the interdialytic phase (48 hrs). In an attempt the prevent clot formation, hospitals routinely administer heparin, an anticoagulant, into the catheter after a dialysis session. It has been reported, however, that up to 40% of the heparin solution will leak into the blood stream during the interdialytic phase, placing the patient at risk for systemic bleeding incidences. The aim of this study is to determine the role that advective-diffusive transport plays in the heparin leaking process. Numerical simulations of heparin convective mass transfer have been conducted, showing that while advective losses may be significant at the tip, previous studies may be overestimating the total amount of heparin leakage. To validate the quantitative prediction from the simulations, P.L.I.F. is used to experimentally measure heparin transport from CVCs placed in an idealized Superior Vena Cava with physically accurate pulsatile flow conditions. Improved understanding of flow near the catheter tip is applied to improve catheter design and heparin locking procedures.

  10. A MODIFIED OPEN SURGERY TECHNIQUE FOR PERITONEAL DIALYSIS CATHETER PLACEMENT DECREASES CATHETER MALFUNCTION.

    PubMed

    Jiang, Chunming; Xu, Linfeng; Chen, Yun; Yan, Xiang; Zhang, Miao; Sun, Cheng

    2013-06-01

    BACKGROUND: This retrospective study was conducted to evaluate the effect of a new, modified open surgery technique on catheter-related malfunction. METHODS: During the period from January 1997 to June 2009, 216 patients received initial peritoneal catheters. For the present study, patients were divided into four groups according to the catheter types and the surgery techniques: • TO-S: traditional open surgery, straight Tenckhoff catheter • TO-C: traditional open surgery, coiled Tenckhoff catheter • TO-SN: traditional open surgery, swan-neck catheter • MO-S: modified open surgery, straight Tenckhoff catheter The modified surgery was characterized by a low incision site, a short intra-abdominal catheter segment and an additional upward straight subcutaneous tunnel. All patients were followed up for 2 years or until death. Survival rates, complications caused by catheter placement, and the probability of malfunction-free catheter survival were compared between the groups. RESULTS: Catheter malfunction was the most frequent mechanical complication, found in 31 patients (14.4%), who experienced 38 malfunctions. Only 2 episodes of catheter malfunction were found in the MO-S group, representing a rate significantly less than those in the TO-S and TO-C groups (both p < 0.05). Kaplan-Meier curves for malfunction-free PD catheter survival showed a significantly different malfunction-free probability for the various groups (p = 0.009). After 2 years of follow-up, 136 patients (63.0%) survived with their initial PD catheter. The initial catheter survival rate was 76.8% in the MO-S group. Kaplan-Meier curves for initial catheter survival showed that the highest survival rate was found in the MO-S group (p = 0.001). CONCLUSIONS: The modified open surgery technique is a reliable method for catheter placement. PMID:23733661

  11. Temporary hemodialysis catheters: recent advances.

    PubMed

    Clark, Edward G; Barsuk, Jeffrey H

    2014-11-01

    The insertion of non-tunneled temporary hemodialysis catheters (NTHCs) is a core procedure of nephrology practice. While urgent dialysis may be life-saving, mechanical and infectious complications related to the insertion of NTHCs can be fatal. In recent years, various techniques that reduce mechanical and infectious complications related to NTHCs have been described. Evidence now suggests that ultrasound guidance should be used for internal jugular and femoral vein NTHC insertions. The implementation of evidence-based infection-control 'bundles' for central venous catheter insertions has significantly reduced the incidence of bloodstream infections in the intensive care unit setting with important implications for how nephrologists should insert NTHCs. In addition, the Cathedia Study has provided the first high-level evidence about the optimal site of NTHC insertion, as it relates to the risk of infection and catheter dysfunction. Incorporating these evidence-based techniques into a simulation-based program for training nephrologists in NTHC insertion has been shown to be an effective way to improve the procedural skills of nephrology trainees. Nonetheless, there are some data suggesting nephrologists have been slow to adopt evidence-based practices surrounding NTHC insertion. This mini review focuses on techniques that reduce the complications of NTHCs and are relevant to the practice and training of nephrologists.

  12. Temperature-controlled cooled-tip radiofrequency ablation in left ventricular myocardium.

    PubMed

    Watanabe, Ichiro; Nuo, Min; Okumura, Yasuo; Ohkubo, Kimie; Ashino, Sonoko; Kofune, Masayoshi; Kofune, Tatsuya; Nakai, Toshiko; Kasamaki, Yuji; Hirayama, Atsushi

    2010-05-01

    Steam pop and intramural charring have been reported during cooled-tip radiofrequency catheter ablation (RFCA). We studied the feasibility of temperature-controlled cooled-tip RFCA in the canine heart.An internally cooled ablation catheter was inserted into the left ventricle. A custom-made radiofrequency (RF) generator capable of controlling the tip-temperature at the preset level by slow increases in the power was used. Temperature-controlled cooled-tip RF applications were performed at a target temperature of 40 degrees C for 90 seconds. Acute study: Intramyocardial temperature was measured at the ablation site in 10 dogs by inserting a fluoroptic probe. Chronic study: Lesion depth and volume were measured in 5 dogs after 3 weeks of survival. In the acute study, no pop or abrupt impedance rise was observed. Maximum intramyocardial temperature was 72.4 + or - 14.4 degrees C at 2-4 mm above the endocardium. No coagulum formation, craters, or intramural charring were observed. Maximum lesion depth was 6.7 + or - 1.5 mm, and lesion volume was 404 + or - 219 mm3. In the chronic study, maximum lesion depth was 5.9 + or - 1.1 mm, and lesion volume was 281 + or - 210 mm(3).Temperature controlled RFCA is feasible with a cooled-tip catheter and an RF generator that slowly increases the RF power until the preset catheter-tip temperature is reached. PMID:20558910

  13. [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.

  14. Management of refractory atrial fibrillation post surgical ablation.

    PubMed

    Altman, Robert K; Proietti, Riccardo; Barrett, Conor D; Paoletti Perini, Alessandro; Santangeli, Pasquale; Danik, Stephan B; Di Biase, Luigi; Natale, Andrea

    2014-01-01

    Over the past two decades, invasive techniques to treat atrial fibrillation (AF) including catheter-based and surgical procedures have evolved along with our understanding of the pathophysiology of this arrhythmia. Surgical treatment of AF may be performed on patients undergoing cardiac surgery for other reasons (concomitant surgical ablation) or as a stand-alone procedure. Advances in technology and technique have made surgical intervention for AF more widespread. Despite improvements in outcome of both catheter-based and surgical treatment for AF, recurrence of atrial arrhythmias following initial invasive therapy may occur.Atrial arrhythmias may occur early or late in the post-operative course after surgical ablation. Early arrhythmias are generally treated with prompt electrical cardioversion with or without antiarrhythmic therapy and do not necessarily represent treatment failure. The mechanism of persistent or late occurring atrial arrhythmias is complex, and these arrhythmias may be resistant to antiarrhythmic drug therapy. The characterization and management of recurrent atrial arrhythmias following surgical ablation of AF are discussed below. PMID:24516805

  15. Management of refractory atrial fibrillation post surgical ablation

    PubMed Central

    Altman, Robert K.; Proietti, Riccardo; Barrett, Conor D.; Paoletti Perini, Alessandro; Santangeli, Pasquale; Danik, Stephan B.; Di Biase, Luigi

    2014-01-01

    Over the past two decades, invasive techniques to treat atrial fibrillation (AF) including catheter-based and surgical procedures have evolved along with our understanding of the pathophysiology of this arrhythmia. Surgical treatment of AF may be performed on patients undergoing cardiac surgery for other reasons (concomitant surgical ablation) or as a stand-alone procedure. Advances in technology and technique have made surgical intervention for AF more widespread. Despite improvements in outcome of both catheter-based and surgical treatment for AF, recurrence of atrial arrhythmias following initial invasive therapy may occur.Atrial arrhythmias may occur early or late in the post-operative course after surgical ablation. Early arrhythmias are generally treated with prompt electrical cardioversion with or without antiarrhythmic therapy and do not necessarily represent treatment failure. The mechanism of persistent or late occurring atrial arrhythmias is complex, and these arrhythmias may be resistant to antiarrhythmic drug therapy. The characterization and management of recurrent atrial arrhythmias following surgical ablation of AF are discussed below. PMID:24516805

  16. Thermal Ablation Modeling for Silicate Materials

    NASA Technical Reports Server (NTRS)

    Chen, Yih-Kanq

    2016-01-01

    A thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in ablation simulations of the meteoroid or glassy Thermal Protection Systems for spacecraft. Time-dependent axi-symmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. For model validation, the surface recession of fused amorphous quartz rod is computed, and the recession predictions reasonably agree with available data. The present parametric studies for two groups of meteoroid earth entry conditions indicate that the mass loss through moving molten layer is negligibly small for heat-flux conditions at around 1 MW/cm(exp. 2).

  17. 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.

  18. Tensile set behavior of Foley catheter balloons.

    PubMed

    Joseph, R; Ramesh, P; Sivakumar, R

    1999-01-01

    The removal of indwelling urinary balloon catheters from patients is usually associated with many problems. The problems such as balloon deflation failure; encrustations on balloons, eyes, and lumen; and catheter associated infections are widely discussed in the literature. The tensile set exhibited by the catheter balloon material could also play a role and further complicate the removal process. This article addresses this issue by comparing the tensile set behavior of the balloon material from three commercially available Foley catheters. The balloon materials were subjected to aging in synthetic urine at 37 degrees C for 28 days to simulate clinical conditions. The deflation time of catheter balloons aged in similar conditions were also measured. It was found that different brands of catheters exhibited statistically significant differences in their properties. The tensile set data of the aged samples could be correlated with the deflation time of the balloons. The clinical significance of the tensile set is also highlighted.

  19. Distance of the internal central venous catheter tip from the right atrium is positively correlated with central venous thrombosis.

    PubMed

    Ballard, David H; Samra, Navdeep S; Gifford, Karen Mathiesen; Roller, Robert; Wolfe, Bruce M; Owings, John T

    2016-06-01

    Central venous catheters (CVCs) are associated with occlusive, infectious, and thrombotic complications. The aim of this study was to determine if internal CVC tip position was correlated with subsequent complications. This was an institutional review board approved single-center retrospective review of 169 consecutive patients who underwent placement of 203 semipermanent CVCs. Using post-placement chest X-rays, a de novo scale of internal catheter tip position was developed. Major complications were recorded. A logistic regression analysis was used to determine if catheter tip position predicted subsequent complications. There were 78 men and 91 women with a mean age of 48 ± 11 years. There were 21 catheter tips placed in the subclavian/innominate veins, 32 in the upper superior vena cava, 113 in the atriocaval junction, and 37 in the right atrium. There were 83 complications occurring in 61 (36.1 %) patients, including sepsis in 40 (23.7 %), venous thrombosis in 18 (10.7 %), catheter occlusion in 16 (9.5 %), internal catheter repositioning in 6 (3.6 %), pneumothorax in 2 (1.2 %), and death in 1 (0.6 %). An internal catheter tip position peripheral to the atriocaval junction resulted in a catheter that was more likely to undergo internal repositioning (p < 0.001) and venous thrombosis (p < 0.001). Patients with femoral catheters were more likely to develop sepsis (45 %) than patients whose catheters were inserted through the upper extremity veins (18 %) (p < 0.01). In conclusion, to reduce catheter-associated morbidity and potentially mortality, the internal catheter tip should be positioned at the atriocaval junction or within the right atrium and femoral insertion sites should be avoided whenever possible.

  20. 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.

  1. Intraoperative 3D stereo visualization for image-guided cardiac ablation

    NASA Astrophysics Data System (ADS)

    Azizian, Mahdi; Patel, Rajni

    2011-03-01

    There are commercial products which provide 3D rendered volumes, reconstructed from electro-anatomical mapping and/or pre-operative CT/MR images of a patient's heart with tools for highlighting target locations for cardiac ablation applications. However, it is not possible to update the three-dimensional (3D) volume intraoperatively to provide the interventional cardiologist with more up-to-date feedback at each instant of time. In this paper, we describe the system we have developed for real-time three-dimensional stereo visualization for cardiac ablation. A 4D ultrasound probe is used to acquire and update a 3D image volume. A magnetic tracking device is used to track the distal part of the ablation catheter in real time and a master-slave robot-assisted system is developed for actuation of a steerable catheter. Three-dimensional ultrasound image volumes go through some processing to make the heart tissue and the catheter more visible. The rendered volume is shown in a virtual environment. The catheter can also be added as a virtual tool to this environment to achieve a higher update rate on the catheter's position. The ultrasound probe is also equipped with an EM tracker which is used for online registration of the ultrasound images and the catheter tracking data. The whole augmented reality scene can be shown stereoscopically to enhance depth perception for the user. We have used transthoracic echocardiography (TTE) instead of the conventional transoesophageal (TEE) or intracardiac (ICE) echocardiogram. A beating heart model has been used to perform the experiments. This method can be used both for diagnostic and therapeutic applications as well as training interventional cardiologists.

  2. In vivo thermal ablation monitoring using ultrasound echo decorrelation imaging.

    PubMed

    Subramanian, Swetha; Rudich, Steven M; Alqadah, Amel; Karunakaran, Chandra Priya; Rao, Marepalli B; Mast, T Douglas

    2014-01-01

    Previous work indicated that ultrasound echo decorrelation imaging can track and quantify changes in echo signals to predict thermal damage during in vitro radiofrequency ablation (RFA). In the in vivo studies reported here, the feasibility of using echo decorrelation imaging as a treatment monitoring tool was assessed. RFA was performed on normal swine liver (N = 5), and ultrasound ablation using image-ablate arrays was performed on rabbit liver implanted with VX2 tumors (N = 2). Echo decorrelation and integrated backscatter were computed from Hilbert transformed pulse-echo data acquired during RFA and ultrasound ablation treatments. Receiver operating characteristic (ROC) curves were employed to assess the ability of echo decorrelation imaging and integrated backscatter to predict ablation. Area under the ROC curves (AUROC) was determined for RFA and ultrasound ablation using echo decorrelation imaging. Ablation was predicted more accurately using echo decorrelation imaging (AUROC = 0.832 and 0.776 for RFA and ultrasound ablation, respectively) than using integrated backscatter (AUROC = 0.734 and 0.494). PMID:24239361

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

    PubMed Central

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

    2010-01-01

    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. PMID:20799788

  4. 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.

  5. Comparing deflection measurements of a magnetically steerable catheter using optical imaging and MRI

    SciTech Connect

    Lillaney, Prasheel Caton, Curtis; Martin, Alastair J.; Losey, Aaron D.; Evans, Leland; Saeed, Maythem; Cooke, Daniel L.; Wilson, Mark W.; Hetts, Steven W.

    2014-02-15

    Purpose: Magnetic resonance imaging (MRI) is an emerging modality for interventional radiology, giving clinicians another tool for minimally invasive image-guided interventional procedures. Difficulties associated with endovascular catheter navigation using MRI guidance led to the development of a magnetically steerable catheter. The focus of this study was to mechanically characterize deflections of two different prototypes of the magnetically steerable catheterin vitro to better understand their efficacy. Methods: A mathematical model for deflection of the magnetically steerable catheter is formulated based on the principle that at equilibrium the mechanical and magnetic torques are equal to each other. Furthermore, two different image based methods for empirically measuring the catheter deflection angle are presented. The first, referred to as the absolute tip method, measures the angle of the line that is tangential to the catheter tip. The second, referred to the base to tip method, is an approximation that is used when it is not possible to measure the angle of the tangent line. Optical images of the catheter deflection are analyzed using the absolute tip method to quantitatively validate the predicted deflections from the mathematical model. Optical images of the catheter deflection are also analyzed using the base to tip method to quantitatively determine the differences between the absolute tip and base to tip methods. Finally, the optical images are compared to MR images using the base to tip method to determine the accuracy of measuring the catheter deflection using MR. Results: The optical catheter deflection angles measured for both catheter prototypes using the absolute tip method fit very well to the mathematical model (R{sup 2} = 0.91 and 0.86 for each prototype, respectively). It was found that the angles measured using the base to tip method were consistently smaller than those measured using the absolute tip method. The deflection angles measured

  6. 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

  7. Impact of different catheter lock strategies on bacterial colonization of permanent central venous hemodialysis catheters.

    PubMed

    Erb, Stefan; Widmer, Andreas F; Tschudin-Sutter, Sarah; Neff, Ursula; Fischer, Manuela; Dickenmann, Michael; Grosse, Philipp

    2013-12-01

    Thirty-nine hemodialysis patients with permanent central venous catheters were analyzed for bacterial catheter colonization comparing different catheter-lock strategies. The closed needleless Tego connector with sodium chloride lock solution was significantly more frequently colonized with bacteria than the standard catheter caps with antimicrobially active citrate lock solution (odds ratio, 0.22 [95% confidence interval, 0.07-0.71]; P = .011).

  8. Laser ablation of dyes

    NASA Astrophysics Data System (ADS)

    Späth, M.; Stuke, M.

    1992-01-01

    High density 50 μs pulses of the UV dyes PPF, POPOP and BBO and of two dyes in the visible region, Xanthen N92 and Fluorol 7GA were generated by laser ablation. Dye powders were pressed with 7800 kp/cm 2 in round pellets which were ablated by exposure to KrF excimer laser radiation (248 nm) at a fluence of 100 mJ/cm 2. The ablation cloud was optically activated with a XeCl excimer laser. Its fluorescence spectrum was measured and was identified as a dye vapour fluorescence spectrum by comparison to conventional dye solution and dye vapour spectra. The dye cloud is not deflected in an electric field (10 6 V/m). By changing the delay time between the ablation laser and the focused activation laser, the velocity distribution of the ablated dye was measured. Its maximum is at 600 m/s for PPF. Knowing the thickness of the ablated dye layer per shot (300 Å) and the size of the ablation cloud (pictures of a video camera), one can estimate the maximum density of the dye in the gas pulse to be 10 -5 mol/ l in the range of concentration of lasing dyes. However, no lasing was observed up to now.

  9. Tumor Ablation and Nanotechnology

    PubMed Central

    Manthe, Rachel L.; Foy, Susan P.; Krishnamurthy, Nishanth; Sharma, Blanka; Labhasetwar, Vinod

    2010-01-01

    Next to surgical resection, tumor ablation is a commonly used intervention in the treatment of solid tumors. Tumor ablation methods include thermal therapies, photodynamic therapy, and reactive oxygen species (ROS) producing agents. Thermal therapies induce tumor cell death via thermal energy and include radiofrequency, microwave, high intensity focused ultrasound, and cryoablation. Photodynamic therapy and ROS producing agents cause increased oxidative stress in tumor cells leading to apoptosis. While these therapies are safe and viable alternatives when resection of malignancies is not feasible, they do have associated limitations that prevent their widespread use in clinical applications. To improve the efficacy of these treatments, nanoparticles are being studied in combination with nonsurgical ablation regimens. In addition to better thermal effect on tumor ablation, nanoparticles can deliver anticancer therapeutics that show synergistic anti-tumor effect in the presence of heat and can also be imaged to achieve precision in therapy. Understanding the molecular mechanism of nanoparticle-mediated tumor ablation could further help engineer nanoparticles of appropriate composition and properties to synergize the ablation effect. This review aims to explore the various types of nonsurgical tumor ablation methods currently used in cancer treatment and potential improvements by nanotechnology applications. PMID:20866097

  10. Type of peritoneal dialysis catheter and outcomes.

    PubMed

    Gallieni, Maurizio; Giordano, Antonino; Pinerolo, Cristina; Cariati, Maurizio

    2015-01-01

    In peritoneal dialysis (PD), a well-functioning catheter is of great importance, because a dysfunctional catheter may be associated with incidence of peritonitis, efficiency of dialysis, and to the overall quality of treatment, representing one of the main barriers to optimal use of PD. When considering the relationship between PD catheter type and outcomes, we should keep in mind the different types of available PD catheters, those that are most commonly used in clinical practice, and the available head-to-head comparisons in the literature. The main differences in PD catheter design include the number of cuffs, the shape of subcutaneous tract (straight vs. swan neck), and the shape of intraperitoneal tract (straight vs. coiled). The availability of the best catheter design and materials, along with a skillful management of PD access, may have the greatest impact on long-term patient outcome on PD. It is now established that the use of straight catheters may improve outcomes and technique survival, but further advances in PD catheter technology can potentially improve technique survival. The self-locating PD catheter is a well established device that has not been fully studied and it may represent, based on the available observational evidence and on the clinical experience, an already existing technological advance deserving further studies. PMID:25751555

  11. Serum inflammatory factors and circulating immunosuppressive cells are predictive markers for efficacy of radiofrequency ablation in non-small-cell lung cancer.

    PubMed

    Schneider, T; Sevko, A; Heussel, C P; Umansky, L; Beckhove, P; Dienemann, H; Safi, S; Utikal, J; Hoffmann, H; Umansky, V

    2015-06-01

    In recent years, percutaneous radiofrequency ablation (RFA) has been developed as a new tool in the treatment of non-small-cell lung cancer (NSCLC) in non-surgical patients. There is growing evidence that RFA-mediated necrosis can modulate host immune responses. Here we analysed serum inflammatory factors as well as immunosuppressive cells in the peripheral blood to discover possible prognostic indicators. Peripheral blood and serum samples were collected before RFA and within 3 months after the treatment in a total of 12 patients. Inflammatory cytokines and growth factors were measured in serum by the Bio-Plex assay. Myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs ) were evaluated in the peripheral blood via flow cytometry. In patients developing local or lymphogenic tumour relapse (n=4), we found an early significant increase in the concentration of tumour necrosis factor (TNF)-α as well as chemokine (C-C motif) ligand (CCL)-2 and CCL-4 compared to patients without relapse (n=4) and healthy donors (n=5). These changes were associated with an elevated activity of circulating MDSC indicated by an increased nitric oxide (NO) production in these cells. Elevated serum levels of TNF-α, CCL-2 and CCL-4 associated with an increased NO production in circulating MDSCs might be an early indicator of the incomplete RFA and subsequently a potential tumour relapse in NSCLC.

  12. Cryo-Balloon Catheter Localization Based on a Support-Vector-Machine Approach.

    PubMed

    Kurzendorfer, Tanja; Mewes, Philip W; Maier, Andreas; Strobel, Norbert; Brost, Alexander

    2016-08-01

    Cryo-balloon catheters have attracted an increasing amount of interest in the medical community as they can reduce patient risk during left atrial pulmonary vein ablation procedures. As cryo-balloon catheters are not equipped with electrodes, they cannot be localized automatically by electro-anatomical mapping systems. As a consequence, X-ray fluoroscopy has remained an important means for guidance during the procedure. Most recently, image guidance methods for fluoroscopy-based procedures have been proposed, but they provide only limited support for cryo-balloon catheters and require significant user interaction. To improve this situation, we propose a novel method for automatic cryo-balloon catheter detection in fluoroscopic images by detecting the cryo-balloon catheter's built-in X-ray marker. Our approach is based on a blob detection algorithm to find possible X-ray marker candidates. Several of these candidates are then excluded using prior knowledge. For the remaining candidates, several catheter specific features are introduced. They are processed using a machine learning approach to arrive at the final X-ray marker position. Our method was evaluated on 75 biplane fluoroscopy images from 40 patients, from two sites, acquired with a biplane angiography system. The method yielded a success rate of 99.0% in plane A and 90.6% in plane B, respectively. The detection achieved an accuracy of 1.00 mm±0.82 mm in plane A and 1.13 mm±0.24 mm in plane B. The localization in 3-D was associated with an average error of 0.36 mm±0.86 mm.

  13. Navigation Systems for Ablation

    PubMed Central

    Wood, B. J.; Kruecker, J.; Abi-Jaoudeh, N; Locklin, J.; Levy, E.; Xu, S.; Solbiati, L.; Kapoor, A.; Amalou, H.; Venkatesan, A.

    2010-01-01

    Navigation systems, devices and intra-procedural software are changing the way we practice interventional oncology. Prior to the development of precision navigation tools integrated with imaging systems, thermal ablation of hard-to-image lesions was highly dependent upon operator experience, spatial skills, and estimation of positron emission tomography-avid or arterial-phase targets. Numerous navigation systems for ablation bring the opportunity for standardization and accuracy that extends our ability to use imaging feedback during procedures. Existing systems and techniques are reviewed, and specific clinical applications for ablation are discussed to better define how these novel technologies address specific clinical needs, and fit into clinical practice. PMID:20656236

  14. In situ treatment of liver using catheter based therapeutic ultrasound with combined imaging and GPS tracking

    NASA Astrophysics Data System (ADS)

    Ghoshal, Goutam; Heffter, Tamas; Williams, Emery; Bromfield, Corinne; Salgaonkar, Vasant; Rund, Laurie; Ehrhardt, John M.; Diederich, Chris J.; Burdette, E. Clif

    2013-02-01

    Extensive surgical procedure or liver transplant still remains the gold standard for treating slow-growing tumors in liver. But only few candidates are suitable for such procedure due to poor liver function, tumors in unresectable locations or presence of other liver diseases. In such situations, minimally invasive surgery may be the best therapeutic procedure. The use of RF, laser and ultrasound ablation techniques has gained considerable interest over the past several years to treat liver diseases. The success of such minimally invasive procedure depends on accurately targeting the desired region and guiding the entire procedure. The purpose of this study is to use ultrasound imaging and GPS tracking system to accurately place a steerable acoustic ablator and multiple temperature sensors in porcine liver in situ. Temperature sensors were place at eight different locations to estimate thermal distribution in the three-dimensional treated volume. Acoustic ablator of center frequency of 7 MHz was used for the experiments. During therapy a maximum temperature of 60-65 °C was observed at a distance 8-10 mm from the center of the ablation transducer. The dose distribution was analyzed and compared with the gross pathology of the treated region. Accurate placement of the acoustic applicator and temperature sensors were achieved using the combined image-guidance and the tracking system. By combining ultrasound imaging and GPS tracking system accurate placement of catheter based acoustic ablation applicator can be achieved in livers in situ.

  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, 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,...

  17. 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,...

  18. 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,...

  19. 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,...

  20. 21 CFR 880.5210 - Intravascular catheter securement device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... catheter securement device is a device with an adhesive backing that is placed over a needle or catheter and is used to keep the hub of the needle or the catheter flat and securely anchored to the skin....

  1. 21 CFR 880.5210 - Intravascular catheter securement device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... catheter securement device is a device with an adhesive backing that is placed over a needle or catheter and is used to keep the hub of the needle or the catheter flat and securely anchored to the skin....

  2. 21 CFR 880.5210 - Intravascular catheter securement device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... catheter securement device is a device with an adhesive backing that is placed over a needle or catheter and is used to keep the hub of the needle or the catheter flat and securely anchored to the skin....

  3. 21 CFR 880.5210 - Intravascular catheter securement device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... catheter securement device is a device with an adhesive backing that is placed over a needle or catheter and is used to keep the hub of the needle or the catheter flat and securely anchored to the skin....

  4. 21 CFR 880.5210 - Intravascular catheter securement device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... catheter securement device is a device with an adhesive backing that is placed over a needle or catheter and is used to keep the hub of the needle or the catheter flat and securely anchored to the skin....

  5. Modeling sublimation of a charring ablator

    NASA Technical Reports Server (NTRS)

    Balhoff, J. F.; Pike, R. W.

    1973-01-01

    The Hertz-Knudsen analysis is shown to accurately predict the sublimation rate from a charring ablator. Porosity is shown to have a significant effect on the surface temperature. The predominant carbon species found in the vapor is C3, which agrees well with the results of previous investigations.

  6. Focal Ablation of Prostate Cancer: Four Roles for MRI Guidance

    PubMed Central

    Sommer, Graham; Bouley, Donna; Gill, Harcharan; Daniel, Bruce; Pauly, Kim Butts; Diederich, Christopher

    2014-01-01

    Introduction There is currently a great deal of interest in the possible use of focal therapies for prostate cancer, since such treatments offer the prospect for control or cure of the primary disease with minimal side effects. Many forms of thermal therapy have been proposed for focal ablation of prostate cancer, including laser, high intensity ultrasound and cryotherapy. This review will demonstrate the important roles that MRI guidance can offer to such focal ablation, focusing on the use of high intensity ultrasonic applicators as an example of one promising technique. Materials and Methods Transurethral and interstitial high intensity ultrasonic applicators, designed specifically for ablation of prostate tissue were tested extensively in vivo in a canine model. The roles of MRI in positioning the devices, monitoring prostate ablation, and depicting ablated tissue were assessed using appropriate MRI sequences. Results MRI guidance provides a very effective tool for the positioning of ablative devices in the prostate, and thermal monitoring successfully predicted ablation of prostate tissue when a threshold of 52°C was achieved. Contrast enhanced MRI accurately depicted the distribution of ablated prostate tissue, which is resorbed at 30 days. Conclusions Guidance of thermal therapies for focal ablation of prostate cancer will likely prove critically dependent on MRI functioning in four separate roles. Our studies indicate that in 3 roles: device positioning; thermal monitoring of prostate ablation; and depiction of ablated prostate tissue, MR techniques are highly accurate and likely to be of great benefit in focal prostate cancer ablation. A fourth critical role, identification of cancer within the gland for targeting of thermal therapy, is more problematic at present, but will likely become practical with further technological advances. PMID:23587506

  7. Moldable cork ablation material

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  8. Central venous catheter malposition due to dialysis catheter: a case report

    PubMed Central

    Singh, Neha; Samson, Sumanth

    2016-01-01

    A 56-year-old man on maintenance hemodialysis was admitted to the intensive care unit with septic shock and coagulopathy. As there was a dialysis catheter in the right internal jugular vein, the left internal jugular vein was cannulated with a central venous catheter to initiate vasopressor therapy. A chest X-ray showed formation of a catheter loop inside the left brachiocephalic vein, probably due to hindrance by the dialysis catheter. This report describes the hurdles encountered, repeated cannulation attempts, and serial chest X-ray findings required to obtain acceptable placement of the catheter tip. PMID:27703638

  9. Dispersive effects in laser ablation plasmas

    NASA Astrophysics Data System (ADS)

    Irimiciuc, Ştefan Andrei; Agop, Maricel; Nica, Petru; Gurlui, Silviu; Mihăileanu, Doina; Toma, Ştefan; Focşa, Cristian

    2014-11-01

    The dynamics of transient plasmas generated by high-fluence nanosecond laser ablation has been investigated by recording the ionic current with a Langmuir probe. Systematic measurements have been carried out on a plasma produced in vacuum by Nd:YAG laser irradiation of a copper target. The temporal evolution of the ionic current for different fluences was investigated, revealing the presence of some periodic oscillations. A theoretical model is proposed in order to describe the nonlinear behavior of the expanding plasma by assuming that the motion curves of the ablated particles are fractals. The behaviors predicted by the proposed theoretical model are in good agreement with the experimental findings.

  10. Laser ablation of concrete.

    SciTech Connect

    Savina, M.

    1998-10-05

    Laser ablation is effective both as an analytical tool and as a means of removing surface coatings. The elemental composition of surfaces can be determined by either mass spectrometry or atomic emission spectroscopy of the atomized effluent. Paint can be removed from aircraft without damage to the underlying aluminum substrate, and environmentally damaged buildings and sculptures can be restored by ablating away deposited grime. A recent application of laser ablation is the removal of radioactive contaminants from the surface and near-surface regions of concrete. We present the results of ablation tests on concrete samples using a high power pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied on various model systems consisting of Type I Portland cement with varying amounts of either fine silica or sand in an effort to understand the effect of substrate composition on ablation rates and mechanisms. A sample of non-contaminated concrete from a nuclear power plant was also studied. In addition, cement and concrete samples were doped with non-radioactive isotopes of elements representative of cooling waterspills, such as cesium and strontium, and analyzed by laser-resorption mass spectrometry to determine the contamination pathways. These samples were also ablated at high power to determine the efficiency with which surface contaminants are removed and captured. The results show that the neat cement matrix melts and vaporizes when little or no sand or aggregate is present. Surface flows of liquid material are readily apparent on the ablated surface and the captured aerosol takes the form of glassy beads up to a few tens of microns in diameter. The presence of sand and aggregate particles causes the material to disaggregate on ablation, with intact particles on the millimeter size scale leaving the surface. Laser resorption mass spectrometric analysis showed that cesium and potassium have similar chemical environments in the

  11. Use of ultrasound guidance to remove entrapped stimulating popliteal catheters

    PubMed Central

    Hulin, James B.; Daniels, Don J.

    2016-01-01

    Peripheral nerve catheters are beneficial for continuous pain relief following surgery or trauma to an extremity. However, spring-loaded peripheral nerve catheters can become uncoiled and entrapped, resulting in difficulty in catheter removal. We present two cases where ultrasound guidance provided significant assistance in the safe removal of entrapped peripheral nerve catheters without neurologic sequelae. One of the catheters was adhered to nearby tissue, and one had become uncoiled and anchored in place by the distal tip. Guidelines for the safe management of entrapped catheters are suggested, including the use of saline injections through the catheter under ultrasound guidance to assist in the evaluation and removal of the catheters. PMID:27034548

  12. Flow Visualization Study of a Pulsating Respiratory Assist Catheter

    PubMed Central

    Budilarto, Stephanus G.; Frankowski, Brian J.; Hattler, Brack G.; Federspiel, William J.

    2007-01-01

    Our group is currently developing an intravenous respiratory assist device that uses a centrally located pulsatile balloon within a hollow fiber bundle to enhance gas exchange rate via active mixing mechanism. We tested the hypothesis that the nonsymmetric inflation and deflation of the balloon lead to both nonuniform balloon‐generated secondary flow and nonuniform gas exchange rate in the fiber bundle. The respiratory catheter was placed in a 1‐in. internal diameter rigid test section of an in vitro flow loop (3 L/min deionized water). Particle image velocimetry (PIV), which was used to map the velocity vector field in the lateral cross‐section, showed that the balloon pulsation generated a nonuniform fluid flow surrounding the respiratory assist catheter. PIV was also used to characterize the fiber bundle movement, which was induced by the balloon pulsation. Gas permeability coefficient of the device was evaluated by using both the fluid velocity and the relative velocity between the fluid and the fiber bundle. The highest difference in the gas permeability coefficient predicted by using the relative velocity was about 17% to 23% (angular direction), which was more uniform than the 49% to 59% variation predicted by using the fluid velocity. The movement of the fiber bundle was responsible for reducing the variation in the fluid velocity passing through the bundle and for minimizing the nonuniformity of the gas permeability coefficient of the respiratory assist catheter. PMID:16340349

  13. Alternatives to Indwelling Catheters Cause Unintended Complications.

    PubMed

    Nguyen, Jessica; Harvey, Ellen M; Lollar, Daniel I; Bradburn, Eric H; Hamill, Mark E; Collier, Bryan R; Love, Katie M

    2016-08-01

    To reduce the risk of catheter-associated urinary tract infection (CAUTI), limiting use of indwelling catheters is encouraged with alternative collection methods and early removal. Adverse effects associated with such practices have not been described. We also determined if CAUTI preventative measures increase the risk of catheter-related complications. We hypothesized that there are complications associated with early removal of indwelling catheters. We described complications associated with indwelling catheterization and intermittent catheterization, and compared complication rates before and after policy updates changed catheterization practices. We performed retrospective cohort analysis of trauma patients admitted between August 1, 2009, and December 31, 2013 who required indwelling catheter. Associations between catheter days and adverse outcomes such as infection, bladder overdistention injury, recatheterization, urinary retention, and patients discharged with indwelling catheter were evaluated. The incidence of CAUTI and the total number of catheter days pre and post policy change were similar. The incidence rate of urinary retention and associated complications has increased since the policy changed. Practices intended to reduce the CAUTI rate are associated with unintended complications, such as urinary retention. Patient safety and quality improvement programs should monitor all complications associated with urinary catheterization practices, not just those that represent financial penalties. PMID:27657581

  14. 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.

  15. 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....

  16. 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....

  17. 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....

  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. Automated Pointing of Cardiac Imaging Catheters.

    PubMed

    Loschak, Paul M; Brattain, Laura J; Howe, Robert D

    2013-12-31

    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.

  20. Spontaneous Intravesical Knotting of Urethral Catheter

    PubMed Central

    2011-01-01

    Infant feeding tubes (IFT) have been universally used as urethral catheters in neonates and children for several decades. Though generally a safe procedure, it may cause significant morbidity if the catheter spontaneously knots inside the bladder. We report this complication in three children including a neonate. PMID:22953288

  1. Pulmonary vein triggers, focal sources, rotors and atrial cardiomyopathy: implications for the choice of the most effective ablation therapy.

    PubMed

    Pison, L; Tilz, R; Jalife, J; Haïssaguerre, M

    2016-05-01

    Understanding of the pathophysiological mechanism(s) underlying atrial fibrillation (AF) is the foundation on which current ablation strategies are built. In the vast majority of patients with paroxysmal AF, the ablation procedure should target the pulmonary veins. In patients with nonparoxysmal AF, however, pulmonary vein isolation alone seems to be insufficient to prevent the arrhythmia. Several recent clinical trials have investigated the concept that rotors (re-entry based on a meandering central core from which spiral waves emanate) might be the mechanism responsible for sustaining AF. Ablation of these localized AF sources is an important step towards substrate-driven procedures in persistent AF. Hybrid AF ablation procedures, based on the integration of endocardial transcatheter and epicardial off-pump surgical techniques, have been introduced to overcome their mutual shortcomings. The long-term results are encouraging, especially in currently challenging settings such as nonparoxysmal AF and failed endocardial catheter ablation procedures. PMID:26991806

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Design Calculations for NIF Convergent Ablator Experiments

    NASA Astrophysics Data System (ADS)

    Olson, R. E.; Callahan, D. A.; Hicks, D. G.; Landen, O. L.; Langer, S. H.; Meezan, N. B.; Spears, B. K.; Widmann, K.; Kline, J. L.; Wilson, D. C.; Petrasso, R. D.; Leeper, R. J.

    2010-11-01

    Design calculations for NIF convergent ablator experiments will be described. The convergent ablator experiments measure the implosion trajectory, velocity, and ablation rate of an x-ray driven capsule and are a important component of the U. S. National Ignition Campaign at NIF. The design calculations are post-processed to provide simulations of the key diagnostics -- 1) Dante measurements of hohlraum x-ray flux and spectrum, 2) streaked radiographs of the imploding ablator shell, 3) wedge range filter measurements of D-He3 proton output spectra, and 4) GXD measurements of the imploded core. The simulated diagnostics will be compared to the experimental measurements to provide an assessment of the accuracy of the design code predictions of hohlraum radiation temperature, capsule ablation rate, implosion velocity, shock flash areal density, and x-ray bang time. Post-shot versions of the design calculations are used to enhance the understanding of the experimental measurements and will assist in choosing parameters for subsequent shots and the path towards optimal ignition capsule tuning. *SNL, LLNL, and LANL are operated under US DOE contracts DE-AC04-94AL85000. DE-AC52-07NA27344, and DE-AC04-94AL85000.

  7. Design calculations for NIF convergent ablator experiments.

    SciTech Connect

    Callahan, Debra; Leeper, Ramon Joe; Spears, B. K.; Zylstra, A.; Seguin, F.; Landen, Otto L.; Petrasso, R. D.; Rinderknecht, H.; Kline, J. L.; Frenje, J.; Wilson, D. C.; Langer, S. H.; Widmann, K.; Meezan, Nathan B.; Hicks, Damien G.; Olson, Richard Edward

    2010-11-01

    Design calculations for NIF convergent ablator experiments will be described. The convergent ablator experiments measure the implosion trajectory, velocity, and ablation rate of an x-ray driven capsule and are a important component of the U. S. National Ignition Campaign at NIF. The design calculations are post-processed to provide simulations of the key diagnostics: (1) Dante measurements of hohlraum x-ray flux and spectrum, (2) streaked radiographs of the imploding ablator shell, (3) wedge range filter measurements of D-He3 proton output spectra, and (4) GXD measurements of the imploded core. The simulated diagnostics will be compared to the experimental measurements to provide an assessment of the accuracy of the design code predictions of hohlraum radiation temperature, capsule ablation rate, implosion velocity, shock flash areal density, and x-ray bang time. Post-shot versions of the design calculations are used to enhance the understanding of the experimental measurements and will assist in choosing parameters for subsequent shots and the path towards optimal ignition capsule tuning.

  8. Design Calculations For NIF Convergent Ablator Experiments

    SciTech Connect

    Olson, R E; Hicks, D G; Meezan, N B; Callahan, D A; Landen, O L; Jones, O S; Langer, S H; Kline, J L; Wilson, D C; Rinderknecht, H; Zylstra, A; Petrasso, R D

    2011-10-25

    The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash rhor, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.

  9. Design calculations for NIF convergent ablator experiments

    NASA Astrophysics Data System (ADS)

    Olson, R. E.; Hicks, D. G.; Meezan, N. B.; Callahan, D. A.; Landen, O. L.; Jones, O. S.; Langer, S. H.; Kline, J. L.; Wilson, D. C.; Rinderknecht, H.; Zylstra, A.; Petrasso, R. D.

    2013-11-01

    The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash ρr, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.

  10. Ablating the ventricular insertion of atrio-fascicular mahaim fiber: could be performed safely?

    PubMed

    Ducceschi, Valentino; Vitale, Raffaele; Sokola, Ewa Anna; Ottaviano, Luca; Sangiuolo, Raffaele; Gregorio, Giovanni

    2009-01-01

    We report a patient who underwent radiofrequency ablation of the distal insertion of an atrio-fascicular accessory pathway with decremental properties because of inability to map a suitable potential alongside the tricuspid annulus. Small, discrete potentials resembling those of Purkinje fiber were found at right ventricular apex. All these potentials showed early activation during tachycardia preceding the QRS onset of various degree. Pace mapping helped to localize the presumed main distal insertion of the atrio-fascicular accessory pathway in a region where damage of the His-purkinje system may ensue. This case report describes catheter ablation of an atriofascicular accessory pathway by targeting its distal (ventricular) insertion site.

  11. Ablating the ventricular insertion of atrio-fascicular Mahaim fiber: what selection criteria should we use?

    PubMed

    Ducceschi, Valentino; Vitale, Raffaele; Ottaviano, Luca; Sokola, Ewa Anna; Sangiuolo, Raffaele; Gregorio, Giovanni

    2009-09-01

    We reported a patient who underwent RF ablation of the distal insertion of an atrio-fascicular accessory pathway with decremental properties because of inability to map a suitable potential alongside the tricuspid annulus. Small, discrete potentials resembling those of purkinje fiber were found at right ventricular apex, all these potentials showed early activation during tachycardia preceding the QRS onset of various degrees. Pace mapping helped to localize the presumed main distal insertion of the atrio-fascicular AP in a region where a damage of the His-purkinje system may ensue. This case report describes catheter ablation of an atriofascicular accessory pathway by targeting its distal (ventricular) insertion site.

  12. Ablation of swallowing-induced atrial tachycardia affects heart rate variability: a case report.

    PubMed

    Hojo, Rintaro; Fukamizu, Seiji; Ishikawa, Tae; Hayashi, Takekuni; Komiyama, Kota; Tanabe, Yasuhiro; Tejima, Tamotsu; Kobayashi, Yoichi; Sakurada, Harumizu

    2014-05-01

    A 47-year-old man underwent slow pathway ablation for slow-fast atrioventricular nodal reentrant tachycardia. Following the procedure, he felt palpitations while swallowing, and swallowing-induced atrial tachycardia was diagnosed. Swallowing-induced atrial tachycardia arose from the right atrium-superior vena cava junction and was cured by catheter ablation. After the procedure, the patient's heart rate variability changed significantly, indicating suppression of parasympathetic nerve activity. In this case, swallowing-induced atrial tachycardia was related to the vagal nerve reflex. Analysis of heart rate variability may be helpful in elucidating the mechanism of swallowing-induced atrial tachycardia.

  13. Cerebrovascular Complications Related to Atrial Fibrillation Ablation and Strategies for Periprocedural Stroke Prevention.

    PubMed

    Csanadi, Zoltan; Nagy-Baló, Edina; Danik, Stephan; Barrett, Conor; Burkhardt, J David; Sanchez, Javier; Santangeli, Pasquale; Santoro, Francesco; Di Biase, Luigi; Natale, Andrea

    2014-03-01

    Transcatheter treatment of atrial fibrillation (AF) is a complex intervention performed in patients who are at inherently increased risk of a thromboembolic complication, including stroke. It is therefore not surprising that cerebrovascular accidents have been among the most feared complications since the inception of AF ablation. While improvements have been made to limit the incidence of thromboembolic events during catheter ablation of AF, the optimal strategy to minimize such complications has yet to be determined. It is hoped that larger trials using periprocedural anticoagulation strategies can be undertaken to definitively address these important concerns. PMID:27063826

  14. Residual {sup 18}F-FDG-PET Uptake 12 Weeks After Stereotactic Ablative Radiotherapy for Stage I Non-Small-Cell Lung Cancer Predicts Local Control

    SciTech Connect

    Bollineni, Vikram Rao; Widder, Joachim; Pruim, Jan; Langendijk, Johannes A.; Wiegman, Erwin M.

    2012-07-15

    Purpose: To investigate the prognostic value of [{sup 18}F]fluorodeoxyglucose positron emission tomography (FDG-PET) uptake at 12 weeks after stereotactic ablative radiotherapy (SABR) for stage I non-small-cell lung cancer (NSCLC). Methods and Materials: From November 2006 to February 2010, 132 medically inoperable patients with proven Stage I NSCLC or FDG-PET-positive primary lung tumors were analyzed retrospectively. SABR consisted of 60 Gy delivered in 3 to 8 fractions. Maximum standardized uptake value (SUV{sub max}) of the treated lesion was assessed 12 weeks after SABR, using FDG-PET. Patients were subsequently followed at regular intervals using computed tomography (CT) scans. Association between post-SABR SUV{sub max} and local control (LC), mediastinal failure, distant failure, overall survival (OS), and disease-specific survival (DSS) was examined. Results: Median follow-up time was 17 months (range, 3-40 months). Median lesion size was 25 mm (range, 9-70 mm). There were 6 local failures: 15 mediastinal failures, 15 distant failures, 13 disease-related deaths, and 16 deaths from intercurrent diseases. Glucose corrected post-SABR median SUV{sub max} was 3.0 (range, 0.55-14.50). Using SUV{sub max} 5.0 as a cutoff, the 2-year LC was 80% versus 97.7% for high versus low SUV{sub max}, yielding an adjusted subhazard ratio (SHR) for high post-SABR SUV{sub max} of 7.3 (95% confidence interval [CI], 1.4-38.5; p = 0.019). Two-year DSS rates were 74% versus 91%, respectively, for high and low SUV{sub max} values (SHR, 2.2; 95% CI, 0.8-6.3; p = 0.113). Two-year OS was 62% versus 81% (hazard ratio [HR], 1.6; 95% CI, 0.7-3.7; p = 0.268). Conclusions: Residual FDG uptake (SUV{sub max} {>=}5.0) 12 weeks after SABR signifies increased risk of local failure. A single FDG-PET scan at 12 weeks could be used to tailor further follow-up according to the risk of failure, especially in patients potentially eligible for salvage surgery.

  15. [Steam ablation of varicose veins].

    PubMed

    van den Bos, Renate R; Malskat, Wendy S J; Neumann, H A M Martino

    2013-01-01

    In many western countries endovenous thermal ablation techniques have largely replaced classical surgery for the treatment of saphenous varicose veins as they are more effective and patient friendly. Because these treatments can be performed under local tumescent anaesthesia, patients can mobilize immediately after the procedure. A new method of thermal ablation is endovenous steam ablation, which is a fast and easy procedure. Steam ablation may cause less pain than laser ablation and it is also cheaper and more flexible than segmental radiofrequency ablation. PMID:23484513

  16. Ablative therapies for renal tumors

    PubMed Central

    Ramanathan, Rajan; Leveillee, Raymond J.

    2010-01-01

    Owing to an increased use of diagnostic imaging for evaluating patients with other abdominal conditions, incidentally discovered kidney masses now account for a majority of renal tumors. Renal ablative therapy is assuming a more important role in patients with borderline renal impairment. Renal ablation uses heat or cold to bring about cell death. Radiofrequency ablation and cryoablation are two such procedures, and 5-year results are now emerging from both modalities. Renal biopsy at the time of ablation is extremely important in order to establish tissue diagnosis. Real-time temperature monitoring at the time of radiofrequency ablation is very useful to ensure adequacy of ablation. PMID:21789083

  17. Dynamics of Laser Ablation in Superfluid ^4He

    NASA Astrophysics Data System (ADS)

    Buelna, X.; Popov, E.; Eloranta, J.

    2016-10-01

    Pulsed laser ablation of metal targets immersed in superfluid ^4He is visualized by time-resolved shadowgraph photography and the products are analyzed by post-experiment atomic force microscopy (AFM) measurements. The expansion dynamics of the gaseous ablation half-bubble on the target surface appears underdamped and follows the predicted behavior for the thermally induced bubble growth mechanism. An inherent instability of the ablation bubble appears near its maximum radius and no tightly focused cavity collapse or rebound events are observed. During the ablation bubble retreat phase, the presence of sharp edges in the target introduces flow patterns that lead to the creation of large classical vortex rings. Furthermore, on the nanometer scale, AFM data reveal that the metal nanoparticles created by laser ablation are trapped in spherical vortex tangles and quantized vortex rings present in the non-equilibrium liquid.

  18. Laser ablation of a turbid medium: Modeling and experimental results

    SciTech Connect

    Brygo, F.; Semerok, A.; Weulersse, J.-M.; Thro, P.-Y.; Oltra, R.

    2006-08-01

    Q-switched Nd:YAG laser ablation of a turbid medium (paint) is studied. The optical properties (absorption coefficient, scattering coefficient, and its anisotropy) of a paint are determined with a multiple scattering model (three-flux model), and from measurements of reflection-transmission of light through thin layers. The energy deposition profiles are calculated at wavelengths of 532 nm and 1.064 {mu}m. They are different from those described by a Lambert-Beer law. In particular, the energy deposition of the laser beam is not maximum on the surface but at some depth inside the medium. The ablated rate was measured for the two wavelengths and compared with the energy deposition profile predicted by the model. This allows us to understand the evolution of the ablated depth with the wavelength: the more the scattering coefficient is higher, the more the ablated depth and the threshold fluence of ablation decrease.

  19. [Radiofrequency ablation in ventricular tachycardia: initial experience and evaluation of its limitations].

    PubMed

    Velázquez, E; Rosas, F; Frank, R; Tonet, J; Fontaine, G; Lascault, G; Gallais, Y

    1994-01-01

    The purpose of this paper is to report our initial experience with radiofrequency catheter ablation in 21 patients with ventricular tachycardia of different etiologies and to evaluate the causes which play a role in its limitation. The results show a low rate of effectiveness: total clinical success of 43%. Nevertheless there was a high success rate in a specific subsets of patients. The results depends on several factors: the electrophysiologic mechanisms and substrates of the tachycardia, the criteria to localize the critical area perpetuating the arrhythmia and the biophysical aspects of radiofrequency energy. Its usefulness is manifested in ventricular tachycardia with structurally normal heart and it has a limited success in cases with organic heart disease. Improvement of technical aspects and better understanding of the mechanisms of the tachycardia and characteristics of the target site will enhance the results of radiofrequency catheter ablation in ventricular tachycardia. PMID:7979818

  20. Micropillar fabrication on bovine cortical bone by direct-write femtosecond laser ablation

    NASA Astrophysics Data System (ADS)

    Lim, Yong C.; Altman, Katrina J.; Farson, Dave F.; Flores, Katharine M.

    2009-11-01

    We investigated fabrication of cylindrical micropillars on bovine cortical bone using direct-write femtosecond laser ablation. The ablation threshold of the material was measured by single-pulse ablation tests, and the incubation coefficient was measured from linear scanned ablation tests. A motion system was programmed to apply multiple layers of concentric rings of pulses to machine pillars of various diameters and heights. The diameter of the top surface of the pillar was found to steadily decrease due to incubation of damage from successive layers of pulses during the machining process. Pillar top diameter was predicted based on a paraxial beam fluence approximation and single-pulse ablation threshold and incubation coefficient measurements. Pillar diameters predicted as successive layers of pulses were applied were well-matched to experiments, confirming that femtosecond laser ablation of the cortical bone was well-modeled by single-pulse ablation threshold measurements and an incubation coefficient.

  1. Refinements in the coating of urethral catheters reduces the incidence of catheter-associated bacteriuria. An experimental and clinical study.

    PubMed

    Liedberg, H; Lundeberg, T; Ekman, P

    1990-01-01

    The tendency to develop bacteriuria during the use of various forms of indwelling catheters was evaluated in a randomized trial in 90 patients. A silver alloy and hydrogel-coated Foley catheter (SHC) was compared to a non-coated catheter (NC) and a catheter coated only with hydrogel (HC). Three patients (10%) with SHC catheters, 10 (33%) patients with HC catheters, and 15 (50%) patients with NC catheters developed bacteriuria (greater than 10(5) organisms/ml). The difference in the rate of bacteriuria after 5 days of catheterization was statistically significant between the SHC catheter and the NC catheter (p less than 0.002). There was no significant difference between the SHC catheter and the HC catheter, nor was there a significant difference between the HC catheter and the NC catheter. The toxic effects, as estimated by the IC50 value, of the urinary catheter material used was elucidated in an experimental fibroblast model. The IC50 value for the NC catheter was 33.9%, HC catheter 72.2% and for the SHC catheter 98.1%.

  2. 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.

  3. [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. PMID:10925517

  4. Catheter associated infections in hemodialysis patients.

    PubMed

    Sanavi, Suzan; Ghods, Ahad; Afshar, Reza

    2007-03-01

    Hemodialysis catheter related infections (HCRI) are one of the major causes of increasing mortality, morbidity and cost of therapy in hemodialysis patients. Prevention of HCRI requires the identification of predisposing risk factors. To determine the frequency of HCRI risk factors, we studied 116 patients (54% male, mean age of 49.5+/-16 years) patients with HCRI between 2003-2004. Forty one percent of the patients were diabetic. There was a history of previous catheter placement and infection in 41% and 32% of patients, respectively. Pathogenic organisms isolated from blood cultures included Staphylococcus-aureus 42%, Coagulase-negative Staphylococci 20%, E. Coli 19%, Enterococci 7%, Streptococcus D 7%, Pseudomonas aeruginosa 4%, and Klebsiella 1%. Bacterial resistance to vancomycin and amikacin was present in 7% and 4% of the cases, respectively. Hemodialysis catheter related blood borne infections comprised 67% of the total blood-borne infections in our hospital. No significant statistical association was found between HCRI and age, gender, diabetes mellitus, serum albumin level <30 g/L, leukocyte count, erythrocyte sedimentation rate, anatomical location of catheter, mean duration of antibiotic therapy, mean catheter duration, frequency of hemodialysis sessions, pathogenic organisms, and history of previous catheter infection. We conclude that the prevalence of pathogenic organisms of HCRI were similar to previous studies. However, bacterial resistance to antibiotics was low. The mean duration of catheter usage was longer than previously reported. PMID:17237890

  5. 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.

  6. 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.

  7. Variations in Alaska tidewater glacier frontal ablation, 1985-2013

    NASA Astrophysics Data System (ADS)

    McNabb, R. W.; Hock, R.; Huss, M.

    2015-01-01

    Our incomplete knowledge of the proportion of mass loss due to frontal ablation (the sum of ice loss through calving and submarine melt) from tidewater glaciers outside of the Greenland and Antarctic ice sheets has been cited as a major hindrance to accurate predictions of global sea level rise. We present a 28 year record (1985-2013) of frontal ablation for 27 Alaska tidewater glaciers (representing 96% of the total tidewater glacier area in the region), calculated from satellite-derived ice velocities and modeled estimates of glacier ice thickness. We account for cross-sectional ice thickness variation, long-term thickness changes, mass lost between an upstream fluxgate and the terminus, and mass change due to changes in terminus position. The total mean rate of frontal ablation for these 27 glaciers over the period 1985-2013 is 15.11 ± 3.63Gta-1. Two glaciers, Hubbard and Columbia, account for approximately 50% of these losses. The regional total ablation has decreased at a rate of 0.14Gta-1 over this time period, likely due to the slowing and thinning of many of the glaciers in the study area. Frontal ablation constitutes only ˜4% of the total annual regional ablation, but roughly 20% of net mass loss. Comparing several commonly used approximations in the calculation of frontal ablation, we find that neglecting cross-sectional thickness variations severely underestimates frontal ablation.

  8. Ablation dynamics in coiled wire-array Z-pinches

    SciTech Connect

    Hall, G. N.; Lebedev, S. V.; Suzuki-Vidal, F.; Swadling, G.; Chittenden, J. P.; Bland, S. N.; Harvey-Thompson, A.; Knapp, P. F.; Blesener, I. C.; McBride, R. D.; Chalenski, D. A.; Blesener, K. S.; Greenly, J. B.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Kusse, B. R.

    2013-02-15

    Experiments to study the ablation dynamics of coiled wire arrays were performed on the MAGPIE generator (1 MA, 240 ns) at Imperial College, and on the COBRA generator at Cornell University's Laboratory of Plasma Studies (1 MA, 100 ns). The MAGPIE generator was used to drive coiled wires in an inverse array configuration to study the distribution of ablated plasma. Using interferometry to study the plasma distribution during the ablation phase, absolute quantitative measurements of electron line density demonstrated very high density contrasts between coiled ablation streams and inter-stream regions many millimetres from the wire. The measured density contrasts for a coiled array were many times greater than that observed for a conventional array with straight wires, indicating that a much greater axial modulation of the ablated plasma may be responsible for the unique implosion dynamics of coiled arrays. Experiments on the COBRA generator were used to study the complex redirection of plasma around a coiled wire that gives rise to the ablation structure exhibited by coiled arrays. Observations of this complex 3D plasma structure were used to validate the current model of coiled array ablation dynamics [Hall et al., Phys. Rev. Lett. 100, 065003 (2008)], demonstrating irrefutably that plasma flow from the wires behaves as predicted. Coiled wires were observed to ablate and implode in the same manner on both machines, indicating that current rise time should not be an issue for the scaling of coiled arrays to larger machines with fast current rise times.

  9. Prostate thermal therapy with catheter-based ultrasound devices and MR thermal monitoring

    NASA Astrophysics Data System (ADS)

    Diederich, Chris J.; Nau, Will H.; Kinsey, Adam; Ross, Tony; Wootton, Jeff; Juang, Titania; Butts-Pauly, Kim; Ricke, Viola; Liu, Erin H.; Chen, Jing; Bouley, Donna M.; Van den Bosch, Maurice; Sommer, Graham

    2007-02-01

    Four types of transurethral applicators were devised for thermal ablation of prostate combined with MR thermal monitoring: sectored tubular transducer devices with directional heating patterns; planar and curvilinear devices with narrow heating patterns; and multi-sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR-compatible motor. Interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with directional or dynamic angular control. In vivo experiments in canine prostate under MR temperature imaging were used to evaluate the heating technology and develop treatment control strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature and thermal dose in multiple slices through the target volume. Sectored tubular, planar, and curvilinear transurethral devices produce directional coagulation zones, extending 15-20 mm radial distance to the outer prostate capsule. Sequential rotation and modulated dwell time can conform thermal ablation to selected regions. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with directional devices can be used to effectively ablate the posterior peripheral zone of the gland while protecting the rectum. The MR derived 52 °C and lethal thermal dose contours (t 43=240 min) allowed for real-time control of the applicators and effectively defined the extent of thermal damage. Catheter-based ultrasound devices, combined with MR thermal monitoring, can produce relatively fast and precise thermal ablation of prostate, with potential for treatment of cancer or BPH.

  10. Transient Ablation of Teflon Hemispheres

    NASA Technical Reports Server (NTRS)

    Arai, Norio; Karashima, Kei-ichi; Sato, Kiyoshi

    1997-01-01

    For high-speed entry of space vehicles into atmospheric environments, ablation is a practical method for alleviating severe aerodynamic heating. Several studies have been undertaken on steady or quasi-steady ablation. However, ablation is a very complicated phenomenon in which a nonequilibrium chemical process is associated with an aerodynamic process that involves changes in body shape with time. Therefore, it seems realistic to consider that ablation is an unsteady phenomenon. In the design of an ablative heat-shield system, since the ultimate purpose of the heat shield is to keep the internal temperature of the space vehicle at a safe level during entry, the transient heat conduction characteristics of the ablator may be critical in the selection of the material and its thickness. This note presents an experimental study of transient ablation of Teflon, with particular emphasis on the change in body shape, the instantaneous internal temperature distribution, and the effect of thermal expansion on ablation rate.

  11. Advanced Ablative TPS

    NASA Technical Reports Server (NTRS)

    Gasch, Matthew J.

    2011-01-01

    Early NASA missions (Gemini, Apollo, Mars Viking) employed new ablative TPS that were tailored for the entry environment. After 40 years, heritage ablative TPS materials using Viking or Pathfinder era materials are at or near their performance limits and will be inadequate for future exploration missions. Significant advances in TPS materials technology are needed in order to enable any subsequent human exploration missions beyond Low Earth Orbit. This poster summarizes some recent progress at NASA in developing families of advanced rigid/conformable and flexible ablators that could potentially be used for thermal protection in planetary entry missions. In particular the effort focuses technologies required to land heavy (approx.40 metric ton) masses on Mars to facilitate future exploration plans.

  12. EM-navigated catheter placement for gynecologic brachytherapy: an accuracy study

    NASA Astrophysics Data System (ADS)

    Mehrtash, Alireza; Damato, Antonio; Pernelle, Guillaume; Barber, Lauren; Farhat, Nabgha; Viswanathan, Akila; Cormack, Robert; Kapur, Tina

    2014-03-01

    Gynecologic malignancies, including cervical, endometrial, ovarian, vaginal and vulvar cancers, cause significant mortality in women worldwide. The standard care for many primary and recurrent gynecologic cancers consists of chemoradiation followed by brachytherapy. In high dose rate (HDR) brachytherapy, intracavitary applicators and /or interstitial needles are placed directly inside the cancerous tissue so as to provide catheters to deliver high doses of radiation. Although technology for the navigation of catheters and needles is well developed for procedures such as prostate biopsy, brain biopsy, and cardiac ablation, it is notably lacking for gynecologic HDR brachytherapy. Using a benchtop study that closely mimics the clinical interstitial gynecologic brachytherapy procedure, we developed a method for evaluating the accuracy of image-guided catheter placement. Future bedside translation of this technology offers the potential benefit of maximizing tumor coverage during catheter placement while avoiding damage to the adjacent organs, for example bladder, rectum and bowel. In the study, two independent experiments were performed on a phantom model to evaluate the targeting accuracy of an electromagnetic (EM) tracking system. The procedure was carried out using a laptop computer (2.1GHz Intel Core i7 computer, 8GB RAM, Windows 7 64-bit), an EM Aurora tracking system with a 1.3mm diameter 6 DOF sensor, and 6F (2 mm) brachytherapy catheters inserted through a Syed-Neblett applicator. The 3D Slicer and PLUS open source software were used to develop the system. The mean of the targeting error was less than 2.9mm, which is comparable to the targeting errors in commercial clinical navigation systems.

  13. EM-Navigated Catheter Placement for Gynecologic Brachytherapy: An Accuracy Study

    PubMed Central

    Mehrtash, Alireza; Damato, Antonio; Pernelle, Guillaume; Barber, Lauren; Farhat, Nabgha; Viswanathan, Akila; Cormack, Robert; Kapur, Tina

    2014-01-01

    Gynecologic malignancies, including cervical, endometrial, ovarian, vaginal and vulvar cancers, cause significant mortality in women worldwide. The standard care for many primary and recurrent gynecologic cancers consists of chemoradiation followed by brachytherapy. In high dose rate (HDR) brachytherapy, intracavitary applicators and/or interstitial needles are placed directly inside the cancerous tissue so as to provide catheters to deliver high doses of radiation. Although technology for the navigation of catheters and needles is well developed for procedures such as prostate biopsy, brain biopsy, and cardiac ablation, it is notably lacking for gynecologic HDR brachytherapy. Using a benchtop study that closely mimics the clinical interstitial gynecologic brachytherapy procedure, we developed a method for evaluating the accuracy of image-guided catheter placement. Future bedside translation of this technology offers the potential benefit of maximizing tumor coverage during catheter placement while avoiding damage to the adjacent organs, for example bladder, rectum and bowel. In the study, two independent experiments were performed on a phantom model to evaluate the targeting accuracy of an electromagnetic (EM) tracking system. The procedure was carried out using a laptop computer (2.1GHz Intel Core i7 computer, 8GB RAM, Windows 7 64-bit), an EM Aurora tracking system with a 1.3mm diameter 6 DOF sensor, and 6F (2 mm) brachytherapy catheters inserted through a Syed-Neblett applicator. The 3D Slicer and PLUS open source software were used to develop the system. The mean of the targeting error was less than 2.9mm, which is comparable to the targeting errors in commercial clinical navigation systems. PMID:25076828

  14. Navigation for fluoroscopy-guided cryo-balloon ablation procedures of atrial fibrillation

    NASA Astrophysics Data System (ADS)

    Bourier, Felix; Brost, Alexander; Kleinoeder, Andreas; Kurzendorfer, Tanja; Koch, Martin; Kiraly, Attila; Schneider, Hans-Juergen; Hornegger, Joachim; Strobel, Norbert; Kurzidim, Klaus

    2012-02-01

    Atrial fibrillation (AFib), the most common arrhythmia, has been identified as a major cause of stroke. The current standard in interventional treatment of AFib is the pulmonary vein isolation (PVI). PVI is guided by fluoroscopy or non-fluoroscopic electro-anatomic mapping systems (EAMS). Either classic point-to-point radio-frequency (RF)- catheter ablation or so-called single-shot-devices like cryo-balloons are used to achieve electrically isolation of the pulmonary veins and the left atrium (LA). Fluoroscopy-based systems render overlay images from pre-operative 3-D data sets which are then merged with fluoroscopic imaging, thereby adding detailed 3-D information to conventional fluoroscopy. EAMS provide tracking and visualization of RF catheters by means of electro-magnetic tracking. Unfortunately, current navigation systems, fluoroscopy-based or EAMS, do not provide tools to localize and visualize single shot devices like cryo-balloon catheters in 3-D. We present a prototype software for fluoroscopy-guided ablation procedures that is capable of superimposing 3-D datasets as well as reconstructing cyro-balloon catheters in 3-D. The 3-D cyro-balloon reconstruction was evaluated on 9 clinical data sets, yielded a reprojected 2-D error of 1.72 mm +/- 1.02 mm.

  15. Catheter-directed Thrombolysis in Acute Superior Vena Cava Syndrome Caused by Central Venous Catheters.

    PubMed

    Cui, Jie; Kawai, Tasuo; Irani, Zubin

    2015-01-01

    Indwelling central venous catheters have been reported to increase the risk of superior venous cava (SVC) syndrome. This case report describes the development of acute SVC syndrome in a 28-year-old woman with end-stage renal disease implanted with a left-side hemodialysis reliable outflow graft and a right-side double lumen hemodialysis catheter via internal jugular veins. Her symptoms were not alleviated after catheter removal and systemic anticoagulation therapy. She was eventually treated with catheter-directed thrombolysis and a predischarge computer tomographic venogram on postthrombolytic procedure day 7 showed patent central veins and patient remained asymptomatic. This case demonstrates that catheter-directed thrombolysis can be safely employed to treat refractory catheter-induced acute SVC syndrome in end-stage renal disease patients.

  16. Guidewire catheter change in central venous catheter biofilm formation in a burn population.

    PubMed

    Kowalewska-Grochowska, K; Richards, R; Moysa, G L; Lam, K; Costerton, J W; King, E G

    1991-10-01

    This study was designed to assess the risk of colonization and biofilm formation of central venous catheters left in situ for seven days vs those changed over a guidewire at three days and removed at seven days. Colonization was determined using scanning and transmission electron microscopy and compared to a special scraping/sonication culture method. Thirty-one catheters were examined, and no difference was found between catheters left in situ (9 of 16 colonized) and those changed over a guidewire (11 of 15 colonized). Colonization rates rose significantly from 4 of 15 catheters at the time of guidewire change to 11 of 15 at 7 days (p less than 0.001). Of the catheters defined as colonized by SEM, the special culture technique showed bacterial growth in only 35 percent, making a negative culture result of dubious value in ruling out catheter colonization. No beneficial effect of guidewire changes in reducing colonization could be demonstrated.

  17. Renal denervation for hypertension: observations and predictions of a founder.

    PubMed

    Esler, Murray

    2014-05-01

    The 6-year anniversary of the first catheter-based renal denervation procedure for resistant hypertension has passed, and the 3-year follow-up results of the Symplicity HTN-1 are now published. At the 'end of the beginning', it is timely to reflect on the observations to-date for this revolutionary therapy, and to predict the next phase in its development and clinical application in hypertension treatment. In essence, on observations to hand, the procedure is efficacious and seems safe and durable. But will the blood pressure lowering truly be permanent (or might it be cancelled out by renal sympathetic nerve regrowth)? How can patient selection for the renal denervation procedure be optimized, given that some patients do not respond with a blood pressure fall? Will blood pressure lowering with renal denervation reduce the rate of clinical cardiovascular endpoints? Will long-term safety be acceptable? Can milder hypertension be cured? And there are unresolved procedural and technical questions: how much renal denervation is optimal; is unilateral denervation, now commonly used, beneficial; will renal denervation show a 'class effect', with the different energy forms now used for renal nerve ablation producing equivalent blood pressure lowering? At the 12-year anniversary, I expect these questions will be answered, and catheter-based renal denervation will have an established clinical role in the care of patients with severe grades of hypertension. Less certain is the common prediction of its application in early, mild hypertension, in parallel with, or even before anti-hypertensive drug prescribing.

  18. Retained Urethral Catheter Secondary to Placement in Proximal Ureter.

    PubMed

    McGregor, Thomas B; Sharda, Rajan

    2016-01-01

    We present an unusual complication secondary to indwelling urethral catheter placement. Routine catheter placement by the obstetrics team in a postpartum female leads to retention of the catheter and inability of its removal by both the obstetrics and urology teams. Although a retained urinary catheter is relatively common, inability to remove a catheter secondary to placement inadvertently into a ureter is extremely rare. In this paper we will discuss the options in removing a retained catheter and present our case of a retained catheter secondary to placement within the right proximal ureter.

  19. Retained Urethral Catheter Secondary to Placement in Proximal Ureter

    PubMed Central

    Sharda, Rajan

    2016-01-01

    We present an unusual complication secondary to indwelling urethral catheter placement. Routine catheter placement by the obstetrics team in a postpartum female leads to retention of the catheter and inability of its removal by both the obstetrics and urology teams. Although a retained urinary catheter is relatively common, inability to remove a catheter secondary to placement inadvertently into a ureter is extremely rare. In this paper we will discuss the options in removing a retained catheter and present our case of a retained catheter secondary to placement within the right proximal ureter. PMID:27144050

  20. Shuttle subscale ablative nozzle tests

    NASA Technical Reports Server (NTRS)

    Powers, L. B.; Bailey, R. L.

    1980-01-01

    Recent subscale nozzle tests have identified new and promising carbon phenolic nozzle ablatives which utilize staple rayon, PAN, and pitch based carbon cloth. A 4-inch throat diameter submerged test nozzle designed for the 48-inch Jet Propulsion Laboratory char motor was used to evaluate five different designs incorporating 20 candidate ablatives. Test results indicate that several pitch and PAN-based carbon phenolic ablatives can provide erosion and char performance equivalent or superior to the present continuous rayon-based SRM ablative.

  1. Thermal ablation in cancer

    PubMed Central

    Liu, Yong; Cao, Cheng-Song; Yu, Yang; Si, Ya-Meng

    2016-01-01

    Radiofrequency ablation (RFA) and cryoablation are alternative forms of therapy used widely in various pathological states, including treatment of carcinogenesis. The reason is that ablation techniques have ability of modulating the immune system. Furthermore, recent studies have applied this form of therapy on tumor microenvironment and in the systematic circulation. Moreover, RFA and cryoablation result in an inflammatory immune response along with tissue disruption. Evidence has demonstrated that these procedures affect carcinogenesis by causing a significant local inflammatory response leading to an immunogenic gene signature. The present review enlightens the current view of these techniques in cancer. PMID:27703520

  2. Stellar Ablation of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.; Horwitz, J. L.

    2007-01-01

    We review observations and theories of the solar ablation of planetary atmospheres, focusing on the terrestrial case where a large magnetosphere holds off the solar wind, so that there is little direct atmospheric impact, but also couples the solar wind electromagnetically to the auroral zones. We consider the photothermal escape flows known as the polar wind or refilling flows, the enhanced mass flux escape flows that result from localized solar wind energy dissipation in the auroral zones, and the resultant enhanced neutral atom escape flows. We term these latter two escape flows the "auroral wind." We review observations and theories of the heating and acceleration of auroral winds, including energy inputs from precipitating particles, electromagnetic energy flux at magnetohydrodynamic and plasma wave frequencies, and acceleration by parallel electric fields and by convection pickup processes also known as "centrifugal acceleration." We consider also the global circulation of ionospheric plasmas within the magnetosphere, their participation in magnetospheric disturbances as absorbers of momentum and energy, and their ultimate loss from the magnetosphere into the downstream solar wind, loading reconnection processes that occur at high altitudes near the magnetospheric boundaries. We consider the role of planetary magnetization and the accumulating evidence of stellar ablation of extrasolar planetary atmospheres. Finally, we suggest and discuss future needs for both the theory and observation of the planetary ionospheres and their role in solar wind interactions, to achieve the generality required for a predictive science of the coupling of stellar and planetary atmospheres over the full range of possible conditions.

  3. Position of Totally Thoracoscopic Surgical Ablation in the Treatment of Atrial Fibrillation: An Alternative Method of Conduction Testing

    PubMed Central

    Sabashnikov, Anton; Weymann, Alexander; Haldar, Shouvik; Soliman, Rafik F.B.; Fatullayev, Javid; Jones, David; Hussain, Wajid; Choi, Yeong-Hoon; Zeriouh, Mohamed; Dohmen, Pascal M.; Popov, Aron-Frederik; Markides, Vias; Wong, Tom; Bahrami, Toufan

    2015-01-01

    Recent advances in surgical techniques and understanding of the pathophysiology of atrial fibrillation has led to the development of a less invasive thoracoscopic surgical treatment including video-assisted bilateral pulmonary vein isolation using bipolar radiofrequency ablation clamps. More recently, the same operation became possible via a totally thoracoscopic approach. In this paper we describe technical aspects of the thoracoscopic approach to surgical treatment of AF and discuss its features, benefits and limitations. Furthermore, we present a new alternative technique of conduction testing using endoscopic multi-electrode recording catheters. An alternative electrophysiological mapping strategy involves a multi-electrode recording catheter designed primarily for percutaneous endocardial electrophysiologic mapping procedure. According to our initial experience, the recordings obtained from the multi-electrode catheters positioned around the pulmonary veins are more accurate than the recordings obtained from the multifunctional ablation and pacing pen. The totally thoracoscopic surgical ablation approach is a feasible and efficient treatment strategy for atrial fibrillation. The conduction testing can be easily and rapidly performed using a multifunctional pen or multi-electrode recording catheter. PMID:25904211

  4. Using urokinase to restore patency in double lumen catheters.

    PubMed

    Northsea, C

    1994-08-01

    All hemodialysis patients with temporary or permanent double lumen catheters are at risk for catheter occlusion. Clinical outcomes and cost-effectiveness of using urokinase, a thrombolytic agent, to declot occluded double lumen dialysis catheters were evaluated for 2 years. Patency was restored in 95 of 102 catheters. These data support the use of urokinase to safely and effectively restore patency, thereby extending the length of time a catheter can be used for dialysis.

  5. Performing Gram stain directly on catheter tips: assessment of the quality of the observation process.

    PubMed

    Guembe, M; Pérez-Granda, M J; Rivera, M L; Martín-Rabadán, P; Bouza, E

    2015-06-01

    A previous study performed in our institution showed that catheter tip (CT) staining by combining acridine orange and Gram stain (GS) before culture anticipated catheter colonization with exhaustive and careful observation by a highly trained technician. Our objective was to assess the validity values of GS without acridine orange on an external smear of CT for predicting catheter colonization and catheter-related bloodstream infection (C-RBSI). We compared different periods of observation and the results of two technicians with different levels of professional experience. Over a 5-month period, the roll-plate technique was preceded by direct GS of all CTs sent to the microbiology laboratory. The reading was taken at ×100 by two observers with different skill levels. Each observer performed a routine examination (3 min along three longitudinal lines) and an exhaustive examination (5 min along five longitudinal lines). The presence of at least one cell was considered positive. All slides were read before culture results were known. We included a total of 271 CTs from 209 patients. The prevalence of catheter colonization and C-RBSI was 16.2 % and 5.1 %, respectively. Routine and exhaustive examinations revealed only 29.5 % and 40.9 % of colonized catheters, respectively (p < 0.001). In contrast, they revealed high negative predictive values for C-RBSI (96.5 % and 96.3 %, respectively). Our study shows that the yield of GS performed directly on CTs is greater when staining is performed exhaustively. However, the decision to implement this approach in daily routine will depend on the prevalence rate of catheter colonization at each institution.

  6. 21 CFR 882.4100 - Ventricular catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identification. A ventricular catheter is a device used to gain access to the cavities of the brain for injection of material into, or removal of material from, the brain. (b) Classification. Class II...

  7. 21 CFR 882.4100 - Ventricular catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identification. A ventricular catheter is a device used to gain access to the cavities of the brain for injection of material into, or removal of material from, the brain. (b) Classification. Class II...

  8. 21 CFR 882.4100 - Ventricular catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identification. A ventricular catheter is a device used to gain access to the cavities of the brain for injection of material into, or removal of material from, the brain. (b) Classification. Class II...

  9. 21 CFR 882.4100 - Ventricular catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. A ventricular catheter is a device used to gain access to the cavities of the brain for injection of material into, or removal of material from, the brain. (b) Classification. Class II...

  10. 21 CFR 882.4100 - Ventricular catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identification. A ventricular catheter is a device used to gain access to the cavities of the brain for injection of material into, or removal of material from, the brain. (b) Classification. Class II...

  11. 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

  12. Something's missing: peripheral intravenous catheter fracture.

    PubMed

    Glassberg, Elon; Lending, Gadi; Abbou, Benyamine; Lipsky, Ari M

    2013-01-01

    We describe a case of peripheral intravenous catheter fracture occurring during a routine training exercise. The supervising instructor immediately placed a venous tourniquet proximal to the insertion site and urgently transported the patient to the hospital. The missing catheter segment was identified within the median cubital vein under ultrasonography and was removed by venous cutdown under local anesthesia. An investigation determined that reinsertion of the needle into the advanced catheter likely caused the fracture and that application of a tourniquet may have prevented embolism of the fractured segment. Our literature review suggested that peripheral intravenous catheter fracture is likely vastly underreported, with only one prior case identified in the English literature. Action was taken following the event to educate all Israeli Defense Force medical providers regarding both proper preventive measures and recognition and treatment of catheter fracture should it occur. This case highlights the importance of health care providers being aware of the possibility of catheter fracture, as well as steps to take to prevent and mitigate its occurrence.

  13. Determination of urethral catheter surface lubricity.

    PubMed

    Kazmierska, Katarzyna; Szwast, Maciej; Ciach, Tomasz

    2008-06-01

    Device for in-vitro measurement of static and kinetic friction coefficient of catheter surface was developed. Tribometer was designed and constructed to work with exchangeable counter-faces (polymers, tissue) and various types of tubes, in wet conditions in order to mimic in-vivo process. Thus seven commercially available urethral catheters, made from vinyl polymers, natural latex with silicone coating, all-silicone or hydrogel coated, and one made from polyvinylchloride with polyurethane/polyvinylpyrrolidone hydrogel coating obtained in our laboratory, were tested against three various counter faces: polymethacrylate (organic glass), inner part of porcine aorta and porcine bladder mucosa. Additionally, the hydrophility/hydrophobity of tested catheters was stated via water wetting contact angle measurement. Super-hydrophilic biomaterials revealed low friction on tissue and hydrophobic counter-face; slightly hydrophobic showed higher friction in both cases, while more hydrophobic manifested low friction on tissue but high on hydrophobic polymer. The smoothest friction characteristic was achieved in all cases on tissue counter-faces. The measured values of the static coefficient of friction of catheters on bladder mucosa counter-face were as follows: the highest (0.15) for vinyl and siliconised latex catheters and 3 folds lower (0.05) for all-silicone ones. Hydrogel coated catheters exhibited the lowest static and kinetic friction factors. PMID:18071872

  14. Excessive Hyperthermic Necrosis of a Pulmonary Lobe after Hypertonic Saline-Enhanced Monopolar Radiofrequency Ablation

    SciTech Connect

    Kim, Tae Sung Lim, Hyo K.; Kim, Hojoong

    2006-02-15

    Although there has been a feasibility study of saline-enhanced radiofrequency ablation of the lung in rabbits, there has been no report on hypertonic saline-enhanced radiofrequency ablation of human pulmonary tumors or its complication. We report a case in which a large necrotic cavity was produced in the lung after hypertonic saline-enhanced radiofrequency ablation of recurrent metastatic tumor from hepatocellular carcinoma. Although hypertonic saline-enhanced radiofrequency ablation is powerful and efficient in local ablation, it is difficult to predict the exact extent of ablation, especially in the lungs. This can be dangerous, as there is a high chance of producing an ablation area much larger than expected and, hence, major complications. Special attention is required not to overablate while using this technique.

  15. Hybrid epicardial and endocardial ablation of a persistent atrial tachycardia arising from the marshall bundle: the importance of a detailed analysis of the local potentials.

    PubMed

    Kuroki, Kenji; Tada, Hiroshi; Kunugida, Fusanori; Sekiguchi, Yukio; Machino, Takeshi; Yamasaki, Hiro; Igarashi, Miyako; Aonuma, Kazutaka

    2015-05-01

    Radiofrequency catheter ablation of an atrial tachycardia (AT) and atrial fibrillation (AF) was performed in a patient with a history of pulmonary vein isolation for paroxysmal AF. The AT exhibited a centrifugal pattern with the posterolateral LA as the earliest activation site. The AT was not terminated by ablation at the endocardial earliest site, but its cycle length was prolonged by ablation at an opposite site within the Vein of Marshall. Finally, the AT was terminated by an energy application at a site 7 mm posteroinferior to the initial earliest activation site. We analyzed the local potentials of each energy delivery site in detail.

  16. Nozzle designs with pitch precursor ablatives

    NASA Technical Reports Server (NTRS)

    Blevins, H. R.; Bedard, R. J.

    1976-01-01

    Recent developments in carbon phenolic ablatives for solid rocket motor nozzles have yielded a pitch precursor carbon fiber offering significant raw material availability and cost saving advantages as compared to conventional rayon precursor material. This paper discusses the results of an experimental program conducted to assess the thermal performance and characterize the thermal properties of pitch precursor carbon phenolic ablatives. The end result of this program is the complete thermal characterization of pitch fabric, pitch mat, hybrid pitch/rayon fabric and pitch mat molding compound. With these properties determined an analytic capability now exists for predicting the thermal performance of these materials in rocket nozzle liner applications. Further planned efforts to verify material performance and analytical prediction procedures through actual rocket motor firings are also discussed.

  17. Predictive value of pyramidal lobe, percentage thyroid uptake and age for ablation outcome after 15 mCi fixed dose of radioiodine-131 in Graves’ disease

    PubMed Central

    Zaman, Maseeh uz; Fatima, Nosheen; Zaman, Unaiza; Sajjad, Zafar; Zaman, Areeba; Tahseen, Rabia

    2015-01-01

    Purpose: The purpose was to find out the efficacy of fixed 15 mCi radioactive iodine-131 (RAI) dose and predictive values of various factors for inducing hypothyroidism in Graves’ disease (GD). Materials and Methods: Retrospective study conducted from January 2012 till August 2014. Patients with GD who had a technetium-99m thyroid scan, thyroid antibodies, received fixed 15 mCi RAI and did follow endocrine clinics for at least 6 months were selected. RAI was considered successful if within 6 months of RAI therapy patients developed hypothyroidism. Results: Of the 370 patients with GD who had RAI during study period, 210 (57%) qualified study criteria. Mean age of patients was 48 ± 15 years with female: male ratio of 69:31, positive thyroid antibodies in 61%, means thyroid uptake of 15.09 ± 11.23%, and presence of pyramidal lobe in 40% of total population. Hypothyroidism was achieved in 161 (77%) patients while 49 (23%) patients failed to achieve it (remained either hyperthyroid or euthyroid on antithyroid medication). Patients who became hypothyroid were significantly younger with higher proportion of presence of thyroid antibodies and pyramidal lobe and lower percentage thyroid uptake than those who failed. Multiple logistic regression analysis revealed that age (odds ratio; OR = 2.074), pyramidal lobe (OR = 3.317), thyroid antibodies (OR = 8.198), and percentage thyroid uptake (OR = 3.043) were found to be significant prognostic risk factors for post-RAI hypothyroidism. Gender was found to have nonsignificant association with the development of hypothyroidism. Receiver operating characteristic analysis revealed age <42 years and thyroid uptake <15% as threshold values for the development of post-RAI hypothyroidism. Conclusion: We conclude that fixed (15 mCi) RAI dose is highly effective in rendering hypothyroidism in patients with GD. Age (≤42 years), thyroid uptake (≤15%) and presence of pyramidal lobe are strong predictors of hypothyroidism and must be

  18. 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. PMID:25978469

  19. 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.

  20. Percutaneous CT-Guided Ablation in the Hepatic Dome: Artificially Induced Pneumothorax for Safe Transpleural Access

    PubMed Central

    Valle, Leonardo Guedes Moreira; Rochal, Rafael Dahmer; Rahal, Antônio; Garcia, Rodrigo Gobbo

    2015-01-01

    Ablative therapies have become a great alternative to surgical treatment of hepatic nodules. Some technical difficulties may negatively influence the effectiveness of this therapy, such as lesions located near the diaphragm. The transthoracic approach is commonly used to access these lesions. However, it is associated with an increased risk of complications, such as pneumothorax, hemothorax, alveolar bleeding, and others. We report a case of a radiofrequency ablation of a lesion in the hepatic dome, where an artificially induced pneumothorax was performed to guarantee a safe and effective access. The air was easily injected by a spinal needle and later aspirated by a single-lumen catheter. Induced pneumothorax shoud be considered in ablation of hepatic dome lesions, mainly when the transhepatic access is not appropriate. PMID:26713179

  1. Long-term Outcomes of Ventricular Tachycardia Ablation in Different Types of Structural Heart Disease

    PubMed Central

    Liang, Jackson J; Santangeli, Pasquale; Callans, David J

    2015-01-01

    Ventricular tachycardia (VT) often occurs in the setting of structural heart disease and can affect patients with ischaemic or nonischaemic cardiomyopathies. Implantable cardioverter-defibrillators (ICDs) provide mortality benefit and are therefore indicated for secondary prevention in patients with sustained VT, but they do not reduce arrhythmia burden. ICD shocks are associated with increased morbidity and mortality, and antiarrhythmic medications are often used to prevent recurrent episodes. Catheter ablation is an effective treatment option for patients with VT in the setting of structural heart disease and, when successful, can reduce the number of ICD shocks. However, whether VT ablation results in a mortality benefit remains unclear. We aim to review the long-term outcomes in patients with different types of structural heart disease treated with VT ablation. PMID:26835122

  2. Comparisons of kinetic ablation models for the capillary discharge

    SciTech Connect

    Li Rui; Li Xingwen; Jia Shenli; Murphy, Anthony B.

    2010-07-15

    The properties of kinetic ablation models are considered in this paper. The widely used kinetic ablation model (model-K) only considers monatomic vapor. A revised model (model-Z) was introduced by taking into account the polyatomic vapor's internal degrees of freedom, as well as the temperature dependence of the average particle mass. In this work, both temperature and pressure dependence of average particle mass and the specific heat ratio {gamma} are taken into account, producing an improved version of model-Z (denoted model-Z{sup *}). Ablation data calculated by model-K and model-Z* for two typical capillary materials are presented. Compared to model-K, model-Z* predicts an increased ablation rate at lower plasma temperature and higher plasma density, and a decreased rate for the opposite conditions. Finally, based on the plasma parameters in a typical discharge cycle, all three models are used to calculate the time-dependent ablation rate and the integrated ablated mass. It is found that the main difference between their results arises because of the different average particle masses near the wall surface, and model-Z* is the most accurate for the discharge cycle considered. Further, it is found that the ablation parameters are highly sensitive to the pressure, in particular, through the pressure dependence of average particle mass.

  3. Targeted Prostate Thermal Therapy with Catheter-Based Ultrasound Devices and MR Thermal Monitoring

    NASA Astrophysics Data System (ADS)

    Diederich, Chris; Ross, Anthony; Kinsey, Adam; Nau, Will H.; Rieke, Viola; Butts Pauly, Kim; Sommer, Graham

    2006-05-01

    Catheter-based ultrasound devices have significant advantages for thermal therapy procedures, including potential for precise spatial and dynamic control of heating patterns to conform to targeted volumes. Interstitial and transurethral ultrasound applicators, with associated treatment strategies, were developed for thermal ablation of prostate combined with MR thermal monitoring. Four types of multielement transurethral applicators were devised, each with different levels of selectivity and intended therapeutic goals: sectored tubular transducer devices with fixed directional heating patterns; planar and lightly focused curvilinear devices with narrow heating patterns; and multi-sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR-compatible motor. Similarly, interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with fixed directional heating patterns (e.g., 180 deg.). In vivo experiments in canine prostate (n=15) under MR temperature imaging were used to evaluate the heating technology and develop treatment strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature contours and thermal dose in multiple slices through the target volume. Sectored transurethral devices produce directional coagulation zones, extending 15-20 mm radial distance to the outer prostate capsule. The curvilinear applicator produces distinct 2-3 mm wide lesions, and with sequential rotation and modulated dwell time can precisely conform thermal ablation to selected areas or the entire prostate gland. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with

  4. 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.

  5. Conjunction of Endocardial and Coronary Venous System Mapping to Ablate Ventricular Arrhythmias

    PubMed Central

    Wo, Hung-Ta; Yeh, Jih-Kai; Chang, Po-Cheng; Wen, Ming-Shien; Wang, Chun-Chieh; Chou, Chung-Chuan; Yeh, San-Jou

    2016-01-01

    Background Ablation of idiopathic ventricular arrhythmias (VAs) with epicardial or intramural origins is technically challenging. Herein, we have described the successful ablation of left VAs via the coronary venous system (CVS) in conjunction with endocardial map guided by three-dimensional electroanatomical map in six patients. Methods Out of a total consecutive 84 patients with symptomatic idiopathic VAs, radiofrequency ablation via the CVS was performed on six patients (7%). Furthermore, we reviewed patient records and electrophysiologic studies with respect to clinical characteristics. Results Activation map was conducted in 5 patients, and the earliest activation sites were identified within the CVS. The preceding times to the onset of QRS complex were longer than those at the earliest endocardial sites (36.2 ± 5.6 ms vs. 14.2 ± 6.4 ms, p = 0.02, n = 5). Spiky fractionated long-duration potentials were recorded at the successful ablation sites in all 5 patients. The other patient received pacemapping only because of few spontaneous VAs during the procedure, and the best pacemap spot was found within the CVS. Irrigated catheters were required in 4 out of 6 patients because VAs were temporarily suppressed with regular ones. Conclusions Idiopathic VAs can be ablated via the CVS in conjunction with endocardial mapping. Additionally, spiky fractionated long-duration potential can function as a clue to identify the good ablation site. PMID:27274177

  6. Ablation of Martian glaciers

    NASA Technical Reports Server (NTRS)

    Moore, Henry J.; Davis, Philip A.

    1987-01-01

    Glacier like landforms are observed in the fretted terrain of Mars in the latitude belts near + or - 42 deg. It was suggested that sublimation or accumulation-ablation rates could be estimated for these glaciers if their shapes were known. To this end, photoclinometric profiles were obtained of a number of these landforms. On the basis of analyses of these profiles, it was concluded that ice is chiefly ablating from these landforms that either are inactive rock-glaciers or have materials within them that are moving exceedingly slowly at this time. These conclusions are consistent with other geologic information. The analyses were performed using a two-dimensional model of an isothermal glacier.

  7. 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

  8. [Ablative and fractional lasers].

    PubMed

    Beylot, C; Grognard, C; Michaud, T

    2009-10-01

    The use of pulsed or scanning Carbon Dioxide, and pulsed Erbium-YAG lasers allows the programmable and reproducible photocoagulation of thin layers of the epidermis and superficial dermis. Thermal damage depends on the type of laser and is greater with CO(2) lasers. The degree of neocollagenesis is proportional to the thermal damage and is better with CO(2) lasers. Their main indication is the correction of photoaged facial skin but they can also be used for corrective dermatology, e.g. for scars and genodermatosis. Results are highly satisfactory but the technique is invasive and the patient experiences a social hindrance of around two weeks. Fractionated techniques treat 25% of the defective skin area at each session in noncontiguous microzones; four sessions are therefore necessary to treat the entire cutaneous surface. The treatment is given under topical anesthesia and is much less invasive, particularly with nonablative fractional laser treatment in which photothermolysis does not penetrate below the epidermis and/or the effects are slight, with no or very little social isolation. However, the results are much less satisfactory than the results of ablative laser and there is no firming effect. Other zones than the face can be treated. With the fractional CO(2) and Erbium ablative lasers, which have multiplied over the past 2 years, the much wider impacts cause perforation of the epidermis and there is a zone of ablation by laser photovaporization, with a zone of thermal damage below. The results are better in correcting photoaging of the face, without, however, achieving the efficacy of ablative lasers, which remain the reference technique. However, the effects are not insignificant, requiring at least 5 days of social isolation.

  9. Nonholonomic catheter path reconstruction using electromagnetic tracking

    NASA Astrophysics Data System (ADS)

    Lugez, Elodie; Sadjadi, Hossein; Akl, Selim G.; Fichtinger, Gabor

    2015-03-01

    Catheter path reconstruction is a necessary step in many clinical procedures, such as cardiovascular interventions and high-dose-rate brachytherapy. To overcome limitations of standard imaging modalities, electromagnetic tracking has been employed to reconstruct catheter paths. However, tracking errors pose a challenge in accurate path reconstructions. We address this challenge by means of a filtering technique incorporating the electromagnetic measurements with the nonholonomic motion constraints of the sensor inside a catheter. The nonholonomic motion model of the sensor within the catheter and the electromagnetic measurement data were integrated using an extended Kalman filter. The performance of our proposed approach was experimentally evaluated using the Ascension's 3D Guidance trakStar electromagnetic tracker. Sensor measurements were recorded during insertions of an electromagnetic sensor (model 55) along ten predefined ground truth paths. Our method was implemented in MATLAB and applied to the measurement data. Our reconstruction results were compared to raw measurements as well as filtered measurements provided by the manufacturer. The mean of the root-mean-square (RMS) errors along the ten paths was 3.7 mm for the raw measurements, and 3.3 mm with manufacturer's filters. Our approach effectively reduced the mean RMS error to 2.7 mm. Compared to other filtering methods, our approach successfully improved the path reconstruction accuracy by exploiting the sensor's nonholonomic motion constraints in its formulation. Our approach seems promising for a variety of clinical procedures involving reconstruction of a catheter path.

  10. Application of finite element analysis for assessing biocompatibility of intra-arterial catheters and probes.

    PubMed

    Bedingham, W; Neavin, T D

    1991-01-01

    A commercial finite element modeling program (FIDAP) was adapted to compute the fluid dynamics of laminar blood flow around an intra-arterial catheter and/or sensor probe. The model provided an accurate transient solution to the Navier-Stokes equations under pulsatile blood flow conditions. To simulate the compliance in the catheter tubing set, a second order convolution integral was incorporated into the boundary conditions. The saline drip rate and catheter compliance could be specified, and the bulk blood flow, blood pressure, and heart rate were varied to simulate specific patient conditions. Analysis of the transient solution was used to assess probable sites for thrombus activation and deposition. The transient velocity and pressure fields identified regions of separated flow and recirculation. The computed shear rates and stresses were used to predict hemolysis, platelet activation, and thrombus formation. Analysis of particle paths provided an estimate of residence times and thrombus deposition sites.

  11. 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.

  12. Six-year experience with swan neck catheters.

    PubMed

    Twardowski, Z J; Prowant, B F; Nichols, W K; Nolph, K D; Khanna, R

    1992-01-01

    From the beginning of our continuous ambulatory peritoneal dialysis (CAPD) program in January 1977 until June 1985, we used Tenckhoff and Toronto Western Hospital catheters. Throughout these years catheter survival probabilities of about 30% at three years persisted unchanged and were similar to survival probabilities reported by the National CAPD Registry special survey for these catheters. The first improvement in catheter results regarding leaks was noted after the adoption of lateral catheter insertion. Malfunction was less using swan neck prototypes from August 1985 to April 1986. The latter catheters were made of 80 degrees arc angle tubing between 8.5 cm spaced cuffs and were inserted in a reversed U-shape tunnel with the incision at the top of the tunnel. The use of these catheters was abandoned because of high cuff extrusion and exit infection rates. The next generation of swan neck catheters, the swan neck Missouri 2 and 3 catheters with straight intraperitoneal segments, improved the results dramatically. These catheters were made of 180 degrees arc angle tubing between 5 or 3 cm spaced cuffs. The estimated survival probability of 61% at three years more than doubled compared to previously used catheters. Recently we modified the intraperitoneal segment of the catheters, replacing the straight segment with a coiled one. These modified catheters, the swan neck Missouri coiled catheters, have been used exclusively since February 1990. In addition to an acceptable survival probability of 88% at one year, there are two major advantages of these catheters, the same as for other coiled catheters: elimination of infusion pain due to a jet effect and pain related to straight catheter tip pressure on the peritoneum experienced by some patients.

  13. OCDR guided laser ablation device

    DOEpatents

    Dasilva, Luiz B.; Colston, Jr., Bill W.; James, Dale L.

    2002-01-01

    A guided laser ablation device. The device includes a mulitmode laser ablation fiber that is surrounded by one or more single mode optical fibers that are used to image in the vicinity of the laser ablation area to prevent tissue damage. The laser ablation device is combined with an optical coherence domain reflectometry (OCDR) unit and with a control unit which initializes the OCDR unit and a high power laser of the ablation device. Data from the OCDR unit is analyzed by the control unit and used to control the high power laser. The OCDR images up to about 3 mm ahead of the ablation surface to enable a user to see sensitive tissue such as a nerve or artery before damaging it by the laser.

  14. A Three-Dimensional Shape-Based Force and Stiffness-Sensing Platform for Tendon-Driven Catheters.

    PubMed

    Kouh Soltani, Minou; Khanmohammadi, Sohrab; Ghalichi, Farzan

    2016-01-01

    This paper presents an efficient shape-based three-axial force and stiffness estimator for active catheters commonly implemented in cardiac ablation. The force-sensing capability provides important feedback for catheterization procedures including real-time control and catheter steering in autonomous navigation systems. The proposed platform is based on the introduced accurate and computationally efficient Cosserat rod model for tendon-driven catheters. The proposed nonlinear Kalman filter formulation for contact force estimation along with the developed catheter model provides a real-time force observer robust to nonlinearities and noise covariance uncertainties. Furthermore, the proposed platform enables stiffness estimation in addition to tip contact force sensing in different operational circumstances. The approach incorporates pose measurements which can be achieved using currently developed pose-sensing systems or imaging techniques. The method makes the approach compatible with the range of forces applied in clinical applications. The simulation and experimental results verify the viability of the introduced force and stiffness-sensing technique. PMID:27367685

  15. A Three-Dimensional Shape-Based Force and Stiffness-Sensing Platform for Tendon-Driven Catheters

    PubMed Central

    Kouh Soltani, Minou; Khanmohammadi, Sohrab; Ghalichi, Farzan

    2016-01-01

    This paper presents an efficient shape-based three-axial force and stiffness estimator for active catheters commonly implemented in cardiac ablation. The force-sensing capability provides important feedback for catheterization procedures including real-time control and catheter steering in autonomous navigation systems. The proposed platform is based on the introduced accurate and computationally efficient Cosserat rod model for tendon-driven catheters. The proposed nonlinear Kalman filter formulation for contact force estimation along with the developed catheter model provides a real-time force observer robust to nonlinearities and noise covariance uncertainties. Furthermore, the proposed platform enables stiffness estimation in addition to tip contact force sensing in different operational circumstances. The approach incorporates pose measurements which can be achieved using currently developed pose-sensing systems or imaging techniques. The method makes the approach compatible with the range of forces applied in clinical applications. The simulation and experimental results verify the viability of the introduced force and stiffness-sensing technique. PMID:27367685

  16. Multiple target laser ablation system

    DOEpatents

    Mashburn, Douglas N.

    1996-01-01

    A laser ablation apparatus and method are provided in which multiple targets consisting of material to be ablated are mounted on a movable support. The material transfer rate is determined for each target material, and these rates are stored in a controller. A position detector determines which target material is in a position to be ablated, and then the controller controls the beam trigger timing and energy level to achieve a desired proportion of each constituent material in the resulting film.

  17. Multiple target laser ablation system

    DOEpatents

    Mashburn, D.N.

    1996-01-09

    A laser ablation apparatus and method are provided in which multiple targets consisting of material to be ablated are mounted on a movable support. The material transfer rate is determined for each target material, and these rates are stored in a controller. A position detector determines which target material is in a position to be ablated, and then the controller controls the beam trigger timing and energy level to achieve a desired proportion of each constituent material in the resulting film. 3 figs.

  18. [Electroanatomical mapping and radiofrequency ablation of tachycardia originating in pulmonary vein in an adult patient].

    PubMed

    Végh, Eszter Mária; Széplaki, Gábor; Szilágyi, Szabolcs; Osztheimer, István; Tahin, Tamás; Merkely, Béla; Gellér, László

    2011-08-21

    A 29-year-old male was admitted to our outpatient clinic because of palpitation and documented narrow QRS arrhythmia. Based on the ECG, supraventricular tachycardia was diagnosed, electrophysiological examination was indicated and ablation therapy was recommended. During positioning of the catheter the patient developed arrhythmia. On the coronary sinus catheter the activation spread from distal to proximal electrodes, suggesting left atrial origin. During atrial entrainment pacing long return cycle was observed and distal coronary sinus pacing resulted in a 15 ms longer cycle length than the arrhythmia. Therefore, the left atrial origin of the arrhythmia was confirmed and double transseptal puncture was performed. Lasso and irrigated tip catheter were introduced into the left atrium and electroanatomical mapping was performed with CARTO3 system. After electroanatomical mapping the origin of tachycardia was located proximally in the left superior pulmonary vein. Ablation was started at the earliest activation point, where acceleration was observed and the arrhythmia stopped after the first ablation. Pulmonary vein isolation was completed, and bidirectional block could be confirmed. After 30 minutes the arrhythmia was not inducible. During follow-up, Holter-examination was negative and the patient remained asymptomatic. The pulmonary vein tachycardia is a supraventricular arrhythmia that can occur at any age, but the diagnosis based on the ECG is not always simple. Detailed electroanatomical mapping is very important in the diagnosis of this type of arrhythmia, although it can be verified with conventional electrophysiological methods as well. Focal ablation may be a therapeutic option; however, total isolation of pulmonary veins can be more effective. PMID:21835744

  19. [Electroanatomical mapping and radiofrequency ablation of tachycardia originating in pulmonary vein in an adult patient].

    PubMed

    Végh, Eszter Mária; Széplaki, Gábor; Szilágyi, Szabolcs; Osztheimer, István; Tahin, Tamás; Merkely, Béla; Gellér, László

    2011-08-21

    A 29-year-old male was admitted to our outpatient clinic because of palpitation and documented narrow QRS arrhythmia. Based on the ECG, supraventricular tachycardia was diagnosed, electrophysiological examination was indicated and ablation therapy was recommended. During positioning of the catheter the patient developed arrhythmia. On the coronary sinus catheter the activation spread from distal to proximal electrodes, suggesting left atrial origin. During atrial entrainment pacing long return cycle was observed and distal coronary sinus pacing resulted in a 15 ms longer cycle length than the arrhythmia. Therefore, the left atrial origin of the arrhythmia was confirmed and double transseptal puncture was performed. Lasso and irrigated tip catheter were introduced into the left atrium and electroanatomical mapping was performed with CARTO3 system. After electroanatomical mapping the origin of tachycardia was located proximally in the left superior pulmonary vein. Ablation was started at the earliest activation point, where acceleration was observed and the arrhythmia stopped after the first ablation. Pulmonary vein isolation was completed, and bidirectional block could be confirmed. After 30 minutes the arrhythmia was not inducible. During follow-up, Holter-examination was negative and the patient remained asymptomatic. The pulmonary vein tachycardia is a supraventricular arrhythmia that can occur at any age, but the diagnosis based on the ECG is not always simple. Detailed electroanatomical mapping is very important in the diagnosis of this type of arrhythmia, although it can be verified with conventional electrophysiological methods as well. Focal ablation may be a therapeutic option; however, total isolation of pulmonary veins can be more effective.

  20. Catheter tip force transducer for cardiovascular research

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Silver, R. H.; Culler, V. H. (Inventor)

    1976-01-01

    A force transducer for measuring dynamic force activity within the heart of a subject essentially consists of a U-shaped beam of low elastic compliance material. Two lines extend from the beams's legs and a long coil spring is attached to the beam. A strain gauge is coupled to one of the beam's legs to sense deflections thereof. The beam with the tines and most of the spring are surrounded by a flexible tube, defining a catheter, which is insertable into a subject's heart through an appropriate artery. The tines are extractable from the catheter for implantation into the myocardium by pushing on the end of the spring which extends beyond the external end of the catheter.

  1. The importance of effective catheter securement.

    PubMed

    Fisher, Jayne

    This article examines the importance of securing/fixing indwelling urinary catheters. The Oxford English dictionary interlinks the two words-'secure' and 'fix'-as having the same meaning. To secure the catheter should not be confused with 'support', whereby the weight of the urine drainage bag is supported with the use of velcro straps or a sleeve. The author introduces the need for the concept of this practice to be at the forefront of nurses' minds in all settings, and this is demonstrated through the use of case studies. Current guidance in this area is reviewed, as well as the problems that can arise when catheters are not secured properly and the available products for health professionals to use. PMID:20948482

  2. The importance of effective catheter securement.

    PubMed

    Fisher, Jayne

    This article examines the importance of securing/fixing indwelling urinary catheters. The Oxford English dictionary interlinks the two words-'secure' and 'fix'-as having the same meaning. To secure the catheter should not be confused with 'support', whereby the weight of the urine drainage bag is supported with the use of velcro straps or a sleeve. The author introduces the need for the concept of this practice to be at the forefront of nurses' minds in all settings, and this is demonstrated through the use of case studies. Current guidance in this area is reviewed, as well as the problems that can arise when catheters are not secured properly and the available products for health professionals to use.

  3. Data fusion for catheter tracking using Kalman filtering: applications in robot-assisted catheter insertion

    NASA Astrophysics Data System (ADS)

    Azizian, Mahdi; Patel, Rajni

    2011-03-01

    X-ray image guided angioplasty is a minimally invasive procedure that involves the insertion of a catheter into a blood vessel to remove blockages to blood flow. There are several issues associated with conventional angioplasty which cause risks for the patient (damage to blood vessels, dislodging plaques, etc.) and difficulties for the clinician (X-ray exposure, fatigue, etc.). Autonomous or semi-autonomous robot-assisted catheter insertion is a solution that can reduce these problems substantially. To perform autonomous catheter insertion, closed-loop position control of the distal tip of the catheter is required during insertion. Therefore accurate real-time position feedback is needed for this purpose. We have developed a real-time image processing algorithm for catheter tip position tracking which has an acceptable performance but is sensitive to X-ray image artifacts caused by bones and dense tissues. A magnetic tracking system (MTS) is another modality that has also been used for catheter tip position tracking, but it is sensitive to external electromagnetic interferences and ferromagnetic material. Combining the measurement data provided by both imaging and magnetic sensors can compensate for the deficiencies of each and can also improve the robustness of catheter tip position tracking. We have developed a Kalman filter based sensor fusion scheme to overcome deficiencies of both of these methods and create a reliable real-time tracking of a catheter tip. Experiments have been performed by inserting a guide catheter into a model of the vasculature. The method has been tested in presence of occlusion in the images and also electromagnetic interference.

  4. 21 CFR 870.1240 - Flow-directed catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... (a) Identification. A flow-directed catheter is a device that incorporates a gas-filled balloon to help direct the catheter to the desired position. (b) Classification. Class II (performance standards)....

  5. 21 CFR 870.1240 - Flow-directed catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (a) Identification. A flow-directed catheter is a device that incorporates a gas-filled balloon to help direct the catheter to the desired position. (b) Classification. Class II (performance standards)....

  6. Non-fluoroscopic catheter visualization using MediGuide™ technology: experience from the first 600 procedures.

    PubMed

    Sommer, P; Richter, S; Hindricks, G; Rolf, S

    2014-09-01

    A novel cardiovascular navigation system known as MediGuide™ (MG) which allows non-fluoroscopic catheter tracking over a background of pre-recorded cine loops was recently introduced. This system allows significant reduction of fluoroscopy exposure which is one of the potentially harmful aspects of today's electrophysiological procedures such as ablations or device implantations. We provide a summary of recently published studies related to this new technological platform and describe our experience from the first 600 MG procedures at our institution.After reviewing the currently available publications in the field of MG-supported EP procedures, we describe the workflows for (1) ablation of supraventricular tachycardia (SVT), atrial fibrillation (AF), and ventricular tachycardia using MG-enabled diagnostic and ablation catheters, as well as (2) implant of cardiac resynchronization therapy (CRT) devices using sensor-equipped delivery tools including sheaths, sub-selectors, and guidewires.As shown in several studies [5-9], MG procedures resulted in similar efficacy as conventional cases but with a significant reduction in fluoroscopy time and dose. In particular, for SVT ablations, the median fluoroscopy time using the MG technology was 0.5 ± 1.4 min compared to 10.2 ± 9.6 min in conventional fluoroscopic settings. Similar reductions were demonstrated for AF ablation procedures from 25 min in conventional settings with electroanatomical mapping systems and live x-ray to 4.6 min with the addition of the MG technology. Recently, it was demonstrated that the application of MG for CRT device implants could successfully result in a median fluoroscopy time of 2.6 min for LV lead deployment.In summary, the first measurable clinical impact of the MG technology on a daily clinical routine is the reduction of fluoroscopy time and radiation exposure for various EP indications. These beneficial effects were achieved without negative consequences on procedural

  7. Ventriculoperitoneal Shunt Peritoneal Catheter Knot Formation

    PubMed Central

    Ul-Haq, Anwar; Al-Otaibi, Faisal; Alshanafey, Saud; Sabbagh, Mohamed Diya; Al Shail, Essam

    2013-01-01

    The ventriculoperitoneal (VP) shunt is a common procedure in pediatric neurosurgery that carries a risk of complications at cranial and abdominal sites. We report on the case of a child with shunt infection and malfunction. The peritoneal catheter was tethered within the abdominal cavity, precluding its removal. Subsequently, laparoscopic exploration identified a knot at the distal end of the peritoneal catheter around the omentum. A new VP shunt was inserted after the infection was healed. This type of complication occurs rarely, so there are a limited number of case reports in the literature. This report is complemented by a literature review. PMID:24109528

  8. Echinocandin and ethanol lock therapy treatment of fungal catheter infections.

    PubMed

    Pieroni, Kevin P; Nespor, Colleen; Poole, Robert L; Kerner, John A; Berquist, William E

    2013-03-01

    Ethanol lock therapy has been implemented to prevent infections of central venous catheters as well as to treat infections. Fungal catheter-associated blood stream infections are historically more difficult to treat and have required removal of central venous catheters. We report the largest case series to date, successfully treating 5 of 7 fungal catheter-associated blood stream infections with ethanol lock therapy and systemic echinocandin administration.

  9. Novel uses of the Proxis embolic protection catheter.

    PubMed

    Brilakis, Emmanouil S; Banerjee, Subhash

    2009-09-01

    The Proxis catheter has been designed for proximal embolic protection during saphenous vein graft interventions. The Proxis catheter's flexible and kink-resistant design, lubricity, and atraumatic tip allow deep seating in target vessels. We describe six challenging percutaneous coronary intervention cases, in which the Proxis catheter was used in arterial grafts, sequential saphenous vein grafts, and native coronary arteries. Deep seating of the Proxis catheter enabled vessel visualization and equipment delivery, allowing successful completion of each case.

  10. 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.

  11. Small Bowel Obstruction Due to Suprapubic Catheter Placement.

    PubMed

    Bonasso, Patrick C; Lucke-Wold, Brandon; Khan, Uzer

    2016-07-01

    Suprapubic catheter placement has associated complications such as bowel injury, bladder injury, or bleeding. This case describes the management of an elderly patient who had suprapubic catheter placement complicated by small bowel obstruction. The catheter had continued production of urine. Further patient treatment required abdominal exploration and bowel resection. PMID:27335801

  12. Small Bowel Obstruction Due to Suprapubic Catheter Placement.

    PubMed

    Bonasso, Patrick C; Lucke-Wold, Brandon; Khan, Uzer

    2016-07-01

    Suprapubic catheter placement has associated complications such as bowel injury, bladder injury, or bleeding. This case describes the management of an elderly patient who had suprapubic catheter placement complicated by small bowel obstruction. The catheter had continued production of urine. Further patient treatment required abdominal exploration and bowel resection.

  13. 21 CFR 876.4020 - Fiberoptic light ureteral catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fiberoptic light ureteral catheter. 876.4020... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4020 Fiberoptic light ureteral catheter. (a) Identification. A fiberoptic light ureteral catheter is a device that consists of...

  14. 21 CFR 870.1230 - Fiberoptic oximeter catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fiberoptic oximeter catheter. 870.1230 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1230 Fiberoptic oximeter catheter. (a) Identification. A fiberoptic oximeter catheter is a device used to estimate the...

  15. 21 CFR 870.1230 - Fiberoptic oximeter catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fiberoptic oximeter catheter. 870.1230 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1230 Fiberoptic oximeter catheter. (a) Identification. A fiberoptic oximeter catheter is a device used to estimate the...

  16. 21 CFR 868.5120 - Anesthesia conduction catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Anesthesia conduction catheter. 868.5120 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5120 Anesthesia conduction catheter. (a) Identification. An anesthesia conduction catheter is a flexible tubular device used to...

  17. 21 CFR 868.5120 - Anesthesia conduction catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anesthesia conduction catheter. 868.5120 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5120 Anesthesia conduction catheter. (a) Identification. An anesthesia conduction catheter is a flexible tubular device used to...

  18. 21 CFR 870.1290 - Steerable catheter control system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Steerable catheter control system. 870.1290... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1290 Steerable catheter control system. (a) Identification. A steerable catheter control system is a device that...

  19. 21 CFR 870.1290 - Steerable catheter control system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Steerable catheter control system. 870.1290... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1290 Steerable catheter control system. (a) Identification. A steerable catheter control system is a device that...

  20. 21 CFR 870.1290 - Steerable catheter control system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Steerable catheter control system. 870.1290... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1290 Steerable catheter control system. (a) Identification. A steerable catheter control system is a device that...

  1. 21 CFR 870.1290 - Steerable catheter control system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Steerable catheter control system. 870.1290... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1290 Steerable catheter control system. (a) Identification. A steerable catheter control system is a device that...

  2. 21 CFR 870.1290 - Steerable catheter control system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Steerable catheter control system. 870.1290... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1290 Steerable catheter control system. (a) Identification. A steerable catheter control system is a device that...

  3. 21 CFR 870.1240 - Flow-directed catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Flow-directed catheter. 870.1240 Section 870.1240...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1240 Flow-directed catheter. (a) Identification. A flow-directed catheter is a device that incorporates a gas-filled balloon...

  4. 21 CFR 870.1240 - Flow-directed catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Flow-directed catheter. 870.1240 Section 870.1240...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1240 Flow-directed catheter. (a) Identification. A flow-directed catheter is a device that incorporates a gas-filled balloon...

  5. 21 CFR 870.1240 - Flow-directed catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Flow-directed catheter. 870.1240 Section 870.1240...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1240 Flow-directed catheter. (a) Identification. A flow-directed catheter is a device that incorporates a gas-filled balloon...

  6. 21 CFR 876.4020 - Fiberoptic light ureteral catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fiberoptic light ureteral catheter. 876.4020... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4020 Fiberoptic light ureteral catheter. (a) Identification. A fiberoptic light ureteral catheter is a device that consists of...

  7. 21 CFR 876.4020 - Fiberoptic light ureteral catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fiberoptic light ureteral catheter. 876.4020... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4020 Fiberoptic light ureteral catheter. (a) Identification. A fiberoptic light ureteral catheter is a device that consists of...

  8. 21 CFR 876.4020 - Fiberoptic light ureteral catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fiberoptic light ureteral catheter. 876.4020... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4020 Fiberoptic light ureteral catheter. (a) Identification. A fiberoptic light ureteral catheter is a device that consists of...

  9. 21 CFR 884.6110 - Assisted reproduction catheters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Assisted reproduction catheters. 884.6110 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6110 Assisted reproduction catheters. (a) Identification. Assisted reproduction catheters are devices used in...

  10. 21 CFR 884.6110 - Assisted reproduction catheters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction catheters. 884.6110 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6110 Assisted reproduction catheters. (a) Identification. Assisted reproduction catheters are devices used in...

  11. 21 CFR 884.6110 - Assisted reproduction catheters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Assisted reproduction catheters. 884.6110 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6110 Assisted reproduction catheters. (a) Identification. Assisted reproduction catheters are devices used in...

  12. 21 CFR 884.6110 - Assisted reproduction catheters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Assisted reproduction catheters. 884.6110 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6110 Assisted reproduction catheters. (a) Identification. Assisted reproduction catheters are devices used in...

  13. 21 CFR 884.6110 - Assisted reproduction catheters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Assisted reproduction catheters. 884.6110 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6110 Assisted reproduction catheters. (a) Identification. Assisted reproduction catheters are devices used in...

  14. Ultrasound assessment of caudal catheter position in infants.

    PubMed

    Roberts, Stephen A; Galvez, Ignacio

    2005-05-01

    The positioning of caudally inserted epidural catheters is crucial to their effectiveness. However, level assessment can be difficult and time consuming. We report the use of ultrasound to assess the catheter position in three patients aged between 1 and 10 months. The advantages and disadvantages of this technique are discussed in relation to other methods of assessing caudal catheter placement. PMID:15828997

  15. 21 CFR 876.5030 - Continent ileostomy catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Continent ileostomy catheter. 876.5030 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5030 Continent ileostomy catheter. (a) Identification. A continent ileostomy catheter is a flexible tubular device used as a...

  16. 21 CFR 876.5030 - Continent ileostomy catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Continent ileostomy catheter. 876.5030 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5030 Continent ileostomy catheter. (a) Identification. A continent ileostomy catheter is a flexible tubular device used as a...

  17. 21 CFR 876.5030 - Continent ileostomy catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Continent ileostomy catheter. 876.5030 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5030 Continent ileostomy catheter. (a) Identification. A continent ileostomy catheter is a flexible tubular device used as a...

  18. 21 CFR 876.5030 - Continent ileostomy catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Continent ileostomy catheter. 876.5030 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5030 Continent ileostomy catheter. (a) Identification. A continent ileostomy catheter is a flexible tubular device used as a...

  19. Multidiagnostic analysis of ultrafast laser ablation of metals with pulse pair irradiation

    NASA Astrophysics Data System (ADS)

    Amoruso, S.; Bruzzese, R.; Wang, X.; O'Connell, G.; Lunney, J. G.

    2010-12-01

    Copper targets are irradiated in the ablation regime by pairs of equal, time-delayed collinear laser pulses separated on a timescale going from ≈2 ps to ≈2 ns. The ablation plume is characterized by ion probe diagnostic, fast imaging, and temporally and spatially resolved optical emission spectroscopy. The variation in the ablation efficiency with the delay between the pulses is analyzed by measuring the ablation crater profile with a contact profilometer. The second laser pulse modifies the characteristics of the plasma plume produced by the first pulse and the ablation efficiency. The different mechanisms involved in double pulse ultrafast laser ablation are identified and discussed. The experimental findings are interpreted in the frame of a simple model of the interaction of the second pulse with the nascent ablation plume produced by the first pulse. This model yields consistent and quantitative agreement with the experimental findings predicting the observed experimental trends of the ablation depth reduction and ion yield increase with the delay between the pulses, as well as the characteristic timescale of the observed changes. The possibility of controlling the characteristics of the plumes produced during ultrafast laser ablation via an efficient coupling of the energy of the second pulse to the various ablation components produced by the first pulse is of particular interest in ultrafast pulsed laser deposition and microprobe analyses of materials.

  20. Matricectomy and nail ablation.

    PubMed

    Baran, Robert; Haneke, Eckart

    2002-11-01

    Matricectomy refers to the complete extirpation of the nail matrix, resulting in permanent nail loss. Usually however, matricectomy is only partial, restricted to one or both lateral horns of the matrix. Nail ablation is the definitive removal of the entire nail organ. The most important common denominator in the successful matricectomy is the total removal or destruction of the matrix tissue. Matricectomy may be indicated for the management of onychauxis, onychogryphosis, congenital nail dystrophies, and chronic painful nail, such as recalcitrant ingrown toenail or split within the medial or lateral one-third of the nail.