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

2016 ◽  
Vol 31 (7) ◽  
pp. 1333-1338
Author(s):  
Michaela Sagerer-Gerhardt ◽  
Helmut P. Weber
Keyword(s):  
Laser Ablation ◽  
Ablation Catheter ◽  
Lesion Formation ◽  
Bovine Myocardium

673Bipolar radiofrequency ablation supported by non-ionic catheter irrigation

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
P R Futyma ◽  
P Kulakowski
Keyword(s):  
Catheter Ablation ◽  
Antiarrhythmic Drugs ◽  
Left Ventricular ◽  
Ablation Catheter ◽  
Safe Distance ◽  
Lesion Formation ◽  
Bipolar Radiofrequency ◽  
Antiarrhythmic Treatment ◽  
Catheter Irrigation

Abstract Introduction Bipolar radiofrequency catheter ablation (Bi-RFCA) or irrigation of ablation catheter (AC) using non-ionic coolant, such as dextrose-5 in water (D5W), are novel ways to improve lesion formation in case of arrhythmia refractoriness. Combination of these two methods has not yet been described. Puprose To determine feasibility and effectiveness of Bi-RFCA additionally supported by non-ionic catheter irrigation for treatment of refractory premature ventricular complexes (PVC) or ventricular tachycardia (VT). Methods Consecutive patients after failed extensive Bi-RFCA or D5W-irrigated ablation for symptomatic PVCs or non-sustained VT (nsVT) underwent Bi-RFCA supported with D5W coolant. Results We ultimately enrolled 2 patients (2 males, age 64 ± 12 years) after failed extensive ablations for the left ventricular summit PVCs and nsVT to undergo Bi-RFCA supported with D5W irrigation of both AC and intracardiac return electrode (IRE). Previous pharmacological antiarrhythmic treatment consisting of at least one drug and catheter ablation failed in both patients. Bi-RFCA was delivered between earliest activation sites located in the left/right aortic commissure and the left pulmonic cusp (Figure). Efforts were made to achieve safe distance from coronary arteries, AC, and IRE.  Bipolar RFCA (35 ± 7W power, 8 ± 4 applications, 199 ± 166s RF time)  led to acute elimination of PVCs in both patients. Baseline impedance oscillated around 250Ω and initial 50-70Ω impedance drop was observed during first 20s of bipolar applications, followed by impedance rise up to 350-450Ω. No steam pop occurred and  there were no complications during procedures. All antiarrhythmic drugs were discontinued. Follow-up lasted 8 ± 2 months, there was no nsVT recurrence and 90,4% PVC burden reduction was achieved: from 30000 to 3100 PVC/day in patient #1 and from 39000 to 3500 PVC/day in patient #2. Both patients remained symptom-free. Conclusion Bi-RFCA can be additionally supported using non-ionic D5W coolant. Such approach is feasible and can be safe and effective. More data on impedance imbalance during D5W-supported bipolar RF applications is warranted. Abstract Figure. Fluoroscopic view and 12-lead ECG

Effects of Open-Irrigated Radiofrequency Ablation Catheter Design on Lesion Formation and Complications: In Vitro Comparison of 6 Different Devices

2013 ◽  
Vol 24 (10) ◽  
pp. 1157-1162 ◽  
Author(s):  
JOSE M. GUERRA ◽  
ESTHER JORGE ◽  
SILVIA RAGA ◽  
CAROLINA GÁLVEZ-MONTÓN ◽  
CONCEPCIÓN ALONSO-MARTÍN ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Ablation Catheter ◽  
Lesion Formation ◽  
Catheter Design ◽  
In Vitro Comparison

scholarly journals Robot-Assisted Stereotactic Laser Ablation in Medically Intractable Epilepsy: Operative Technique

2014 ◽  
Vol 10 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Jorge Gonzalez-Martinez ◽  
Sumeet Vadera ◽  
Jeffrey Mullin ◽  
Rei Enatsu ◽  
Andreas V. Alexopoulos ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Minimally Invasive ◽  
Brain Lesion ◽  
Intractable Epilepsy ◽  
Skin Incision ◽  
Ablation Catheter ◽  
Robot Assisted ◽  
Invasive Approach ◽  
T1 Contrast ◽  
Magnetic Resonance Imaging Mri

Abstract BACKGROUND: Stereotactic laser ablation offers an advantage over open surgical procedures for treatment of epileptic foci, tumors, and other brain pathology. Robot-assisted stereotactic laser ablation could offer an accurate, efficient, minimally invasive, and safe method for placement of an ablation catheter into the target. OBJECTIVE: To determine the feasibility of placement of a stereotactic laser ablation catheter into a brain lesion with the use of robotic assistance, via a safe, accurate, efficient, and minimally invasive manner. METHODS: A laser ablation catheter (Visualase, Inc) was placed by using robotic guidance (ROSA, Medtech Surgical, Inc) under general anesthesia into a localized epileptogenic periventricular heterotopic lesion in a 19-year-old woman with 10-year refractory focal seizure history. The laser applicator (1.65 mm diameter) position was confirmed by using magnetic resonance imaging (MRI). Ablation using the Visualase system was performed under multiplanar imaging with real-time thermal imaging and treatment estimates in each plane. A postablation MRI sequence (T1 postgadolinium contrast injection) was used to immediately confirm the ablation. RESULTS: MRI showed accurate skin entry point and trajectory, with the applicator advanced to the lesion's distal boundary. Ablation was accomplished in less than 3 minutes of heating. The overall procedure, from time of skin incision to end of last ablation, was approximately 90 minutes. After confirmation of proper lesioning by using a T1 contrast-enhanced MRI, the applicator was removed, and the incision was closed using a single stitch. No hemorrhage or other untoward complication was visualized. The patient awoke without any complication, was observed overnight after admitting to a regular floor bed, and was discharged to home the following day. CONCLUSION: This technique, using a combination of Visualase laser ablation, ROSA robot, and intraoperative MRI, facilitated a safe, efficacious, efficient, and minimally invasive approach that could be used for placement of 1 or multiple electrodes in the future.

Not only power and energy but also balloon size is correlated with lesion formation in laser ablation model in vitro study

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Matsunaga ◽  
Y Egami ◽  
M Yano ◽  
M Yamato ◽  
R Shutta ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Lesion Formation ◽  
Maximum Width ◽  
Lesion Depth ◽  
Balloon Size ◽  
Balloon Ablation ◽  
Power And Energy ◽  
Laser Balloon Ablation ◽  
Laser Balloon

Abstract Background Power and total energy were known to correlate with lesion formation during laser balloon ablation for atrial fibrillation. However, it is unclear whether balloon size can influence lesion formation. The aim of this study was to evaluate the impact of balloon size on lesion formation during laser balloon procedure in vitro model. Methods Laser energy was applied to chicken muscles using first generation laser balloon. Laser ablation was performed with different 2 balloon size (18mm and 32mm) using 2 different power settings (12W/20sec and 8.5W/20sec). Forty lesions were evaluated for each setting. We compared maximum lesion width, maximum lesion depth, depth at maximum width and endocardial lesion width between 18mm and 32mm balloon groups at 12W/20sec and 8.5W/20sec, respectively. Results At 8.5W/20sec, inadequate lesion formation to assess lesion size was observed in 1/40 lesion of 18mm balloon group and in 5/40 lesions of 32mm balloon group. Thus, at 8.5W/20sec 18 mm balloon group consisted of 39 lesions and 32 mm balloon group consisted of 35 lesions. At 12W/20sec 18 mm balloon group consisted of 40 lesions and 32 mm balloon group consisted of 40 lesions. At both power settings, maximum lesion depth was larger in 18mm balloon than in 32mm balloon group. At 12W/20sec setting, maximum lesion width and endocardial width were larger in 32mm balloon group than in 18mm balloon group. At 12W/20sec setting, depth at maximum width was smaller in 32mm balloon group than in 18mm balloon group. Lesion morphologies were summarized in a figure. Conclusion Balloon size could affect lesion formation during laser balloon ablation in addition to laser power and energy. Laser ablation lesion were wider but shallower in 32mm balloon group compared with in 18mm balloon group. Funding Acknowledgement Type of funding source: None

scholarly journals First clinical experience using a novel temperature-guided ablation catheter in a routine workflow for atrial fibrillation ablation

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
M Braun ◽  
L Bergau ◽  
M Piran ◽  
M El Hamriti ◽  
G Imnadze ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Real Time ◽  
Pulmonary Veins ◽  
Control Mode ◽  
Tissue Temperature ◽  
Ablation Catheter ◽  
Lesion Formation ◽  
Clinical Series ◽  
Temperature Controlled ◽  
Clinical Conditions

Abstract Funding Acknowledgements Type of funding sources: None. Background Recently, a novel irrigated RF catheter was designed with a diamond-embedded tip for rapid cooling and 6 surface thermocouples to reflect real-time tissue temperature. The new technology allows for temperature-controlled irrigated ablation, very high-resolution electrograms (EGMs) from the split-tip electrode, as well as real-time rapid lesion assessment. Aim This study aimed to access clinical performance in terms of lesion formation and procedural safety of the novel DiamondTemp (DT) ablation catheter for atrial fibrillation (AF) ablation under routine clinical conditions. Methods In this prospective observational study, 20 patients underwent pulmonary vein isolation (PVI) with the DT catheter in a temperature control mode (60C°/50 W/ 10 seconds). The ipsilateral pulmonary veins (PV) were divided into 6 anatomical segments (12 segments in total) to record ablation data. All patients underwent preprocedural imaging (computer tomography or magnetic resonance imaging (MRI)) and 10 patients received additional postprocedural late gadolinium enhancement (LGE) MRI of the left atrium 3 months after ablation to access lesion formation for each anatomical PV segment and to rule out PV stenosis. Results Acute PVI was achieved in all patients. Two patients received additional ablation at the cavotricuspid isthmus due to typical atrial flutter. No charring at the catheter tip was found and no procedure related complications were observed. The mean procedure duration (skin-to-skin) was 106 ± 31.9 minutes, mean LA dwell time was 83 ± 27.0 minutes. RF time was 13.5 ± 5.5 minutes with a mean of 74 ± 32.8 RF applications. We measured a mean impedance drop per RF application of 10.7 ± 4.1 ohm. Fluoroscopy time was 4.2 ± 2.3 minutes and the fluoroscopy dose was 221 ± 215.3 cGy*cm2 at a. LGE MRI at 3 months after ablation demonstrated a homogeneous and continuous ablation lesion set around the ipsilateral PVs and there was no evidence for PV stenosis. Conclusions This first clinical series demonstrated that temperature-controlled irrigated ablation resulted in rapid, efficient, and durable PV isolation under routine clinical conditions.

Efficacy of High Temporal Frequency Photoacoustic Guidance of Laser Ablation Procedures

2021 ◽  
Vol 43 (3) ◽  
pp. 149-156
Author(s):  
Yan Yan ◽  
Samuel John ◽  
Jurgita Meiliute ◽  
Loay Kabbani ◽  
Mohammad Mehrmohammadi
Keyword(s):  
Laser Ablation ◽  
Temporal Resolution ◽  
Ex Vivo ◽  
Temporal Frequency ◽  
Frame Rate ◽  
Ablation Catheter ◽  
Temperature Feedback ◽  
Catheter Tip ◽  
Rapid Temperature ◽  
Excised Tissue

Inaccurate placement of the ablation catheter and the inability to monitor the real-time temperature within the tissue of interest such as veins curbs the treatment efficacy of laser ablation procedures during thermal therapies. Our previous studies have validated the efficacy of photoacoustic (PA) imaging during endovenous laser ablation (EVLA) procedures. However, the PA-guided therapies suffer from low temporal resolution, due to the low pulse repetition rates of pulsed lasers, which could cause a problem during fast catheter motion and rapid temperature changes. Herein, to enhance the accuracy and sensitivity for tracking the ablation catheter tip and temperature monitoring, we proposed to develop a high frame rate (500 Hz), combined ultrasound (US), and PA-guided ablation system. The proposed PA-guided ablation system was evaluated in a set of ex vivo tissue studies. The developed system provides a 2 ms temporal resolution for tracking and monitoring the ablation catheter tip’s location and temperature, which is 50 times higher temporal resolution compared to the previously proposed 10 Hz system. The proposed system also provided more accurate feedback about the temperature variations during rapid temperature increments of 10°C per 250 ms. The co-registered US and PA images have an imaging resolution of about 200 μm and a field of view of 45 × 40 mm2. Tracking the ablation catheter tip in an excised tissue layer shows higher accuracy during a relatively fast catheter motion (0.5–3 mm/s). The fast US/PA-guided ablation system will potentially enhance the outcome of ablation procedures by providing location and temperature feedback.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

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