scholarly journals Catheter contact angle influences local impedance drop during radiofrequency catheter ablation: Insight from a porcine experimental study with 2 different LI-sensing catheters

2021 ◽  
Author(s):  
Gen Matsuura ◽  
Hidehira Fukaya ◽  
Emiyu Ogawa ◽  
Sota Kawakami ◽  
Hitoshi Mori ◽  
...  
Keyword(s):  
Experimental Study ◽  
Contact Angle ◽  
Catheter Ablation ◽  
Angular Dependence ◽  
Radiofrequency Catheter Ablation ◽  
Lesion Size ◽  
Contact Angles ◽  
The Other ◽  
Tissue Temperature ◽  
The Difference

Background: Local impedance (LI) can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). However, data on the effects of catheter contact angle on LI parameters are scarce. This study aimed to evaluate the influence of catheter contact angle on LI changes and lesion size with 2 different LI-sensing catheters in a porcine experimental study. Methods: Lesions were created by the INTELLANAV MiFi™ OI (MiFi) and the INTELLANAV STABLEPOINT™ (STABLEPOINT). RFCA was performed with 30 watts and a duration of 30 seconds. The CF (0, 5, 10, 20, and 30 g) and catheter contact angle (30°, 45°, and 90°) were changed in each set (n=8 each). The LI rise, LI drop, and lesion size were evaluated. Results: The LI rise increased as CF increased. There was no angular dependence with the LI rise under all CFs in the MiFi. On the other hand, the LI rise at 90° was lower than at 30° under 5 and 10 g of CF in STABLEPOINT. The LI drop increased as CF increased. Regarding the difference in catheter contact angles, the LI drop at 90° was lower than that at 30° for both catheters. The maximum lesion widths and surface widths were smaller at 90° than at 30°, whereas there were no differences in lesion depths. Conclusion: The LI drop and lesion widths at 90° were significantly smaller than those at 30°, although the lesion depths were not different among the 3 angles for the MiFi and STABLEPOINT.

scholarly journals Catheter contact angle influences local impedance drop during radiofrequency catheter ablation: insight from a porcine experimental study

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
G Matsuura ◽  
H Fukaya ◽  
E Ogawa ◽  
S Kawakami ◽  
D Saito ◽  
...  
Keyword(s):  
Experimental Study ◽  
Contact Angle ◽  
Catheter Ablation ◽  
Radiofrequency Catheter Ablation ◽  
Lesion Size ◽  
Contact Angles ◽  
Tissue Temperature ◽  
Ablation Catheter ◽  
Lesion Depth ◽  
The Difference

Abstract Background Local impedance (LI) at a distal tip of the ablation catheter can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). LI decreases by RFCA, and a degree of LI drop is correlated with lesion size. However, data on the effects of catheter contact angle on lesion size and LI drop were scarce. This study aimed to evaluate the influence of catheter contact angle on lesion size and LI drop in a porcine experimental study. Methods Lesions were created on porcine myocardial left ventricles by the LI-sensing ablation catheter (IntellaNav MiFi OI®). Contact force (CF) was measured using pressure to current transducer (load cell). Radiofrequency ablation was performed with a power of 30 Watt and a duration of 30 seconds. CF (0g, 5g, 10g, 20g, and 30g) and catheter angle (30°, 45°, and 90°) were changed in each set (total 120 lesions, n=8 each). LI rise, LI drop by RF application, and lesion size (maximum lesion width, maximum surface width, and maximum lesion depth) were evaluated. Results There was no angular dependence in LI rise in all CF. The values of LI rise increased as CF increased. The LI drop also increased as CF increased in all contact angles. Regarding the difference of catheter angles, LI drop with 90° was lower than those with 30° and 45°in CF 10g, 20g, and 30g, respectively. Maximum lesion width and surface width were larger in 30° and 45° than those in 90°, whereas there were no differences in maximum lesion depth. Conclusion LI drop in 90° were significantly lower than those in 45° and 30°. Although lesion depths were not different among the three angles, the absolute values of LI drop were different. Caution should be exercised to comprehend the LI drop with catheter angles. FUNDunding Acknowledgement Type of funding sources: None.

scholarly journals Catheter contact area strongly correlates with lesion area in radiofrequency cardiac ablation: an ex vivo porcine heart study

2021 ◽  
Author(s):  
Kriengsak Masnok ◽  
Nobuo Watanabe
Keyword(s):  
Contact Angle ◽  
Catheter Ablation ◽  
Contact Force ◽  
Contact Area ◽  
Radiofrequency Catheter Ablation ◽  
Contact Angles ◽  
Contact Forces ◽  
Ablation Lesion ◽  
Lesion Area ◽  
Lesion Depth

Abstract Purpose Our previous study confirmed that not only force but also the catheter contact angle substantially impacted the contact area and its morphology. Therefore, in this study, we aimed to further investigate the relationship between the catheter contact area and the dimensions of the ablation lesion area as a function of catheter contact angle and force in radiofrequency catheter ablation. Methods The radiofrequency catheter ablation test was performed for 5 contact angles and 8 contact forces at a fixed ablation time of 30 s. The initial impedance was 92.5 ± 2.5 Ω, the temperature during ablation was 30 °C, and the power was 30 W. The irrigation rate during ablation was set to 17 mL/min. Each experiment was repeated 6 times. Results The catheter contact area showed a strong correlation with the ablation lesion area (r = 0.8507). When the contact area was increased, the lesion area also increased linearly in a monotonic manner. The relationships between catheter contact force and ablation lesion area and between catheter contact force and ablation lesion depth are logarithmic functions in which increased contact force was associated with increased lesion area and depth. The catheter contact angle is also an important determinant of the lesion area. The lesion area progressively increased when the contact angle was decreased. In contrast, the lesion depth progressively increased when the contact angle was increased. Conclusions The catheter contact area was strongly correlated with the ablation lesion area. Additionally, catheter contact force and contact angle significantly impacted the dimensions of the lesion in radiofrequency catheter ablation procedures.

Beneficiation of Seafloor Massive Sulfides by Liquid-Liquid Extraction

2021 ◽  
pp. 1-35
Author(s):  
Yasuharu Nakajima ◽  
Yuta Yamabe ◽  
Toyohisa Fujita ◽  
Gjergj Dodbiba
Keyword(s):  
Aqueous Solution ◽  
Contact Angle ◽  
High Pressures ◽  
Sulfide Mineral ◽  
Contact Angles ◽  
Liquid Extraction ◽  
Massive Sulfides ◽  
Liquid Liquid Extraction ◽  
Pressure Extraction ◽  
The Difference

Abstract This paper addresses the applicability of liquid-liquid extraction for separating mineral particles by the difference in oil-water partition coefficient, for the seafloor mineral processing of Seafloor Massive Sulfides (SMSs). Measurements of contact angle of sulfide mineral – aqueous solution – oil systems under high-pressure conditions were performed to evaluate the efficiency of liquid-liquid extraction at high pressures. The results showed that the contact angle stayed around 80 - 100° at the pressure range up to 16MPa; and the changes in the contact angles were within 5° with varying pressure. Extraction experiments were carried out by using particles of an SMS ore, which contained Zinc (Zn), Lead (Pb), and Barium (Ba) in the grade of more than 10 mass% and Copper (Cu) in a small percentage, to evaluate the beneficiation performance of liquid-liquid extraction. In the experiments, extraction conditions such as the dosage of chemical reagents, and pH in the aqueous solution were varied to optimize both the recovery and selectivity of Cu, Zn, and Pb in the oil phase, and those of Ba in the water phase. The experimental results showed that the optimum condition was 200 g/t dosage - pH 7, where the grade and recovery were ca. 37 mass% and ca. 90 mass%, respectively. The beneficiation performance of liquid-liquid extraction would be comparable to that of flotation, adapted to the processing of other SMS ores.

scholarly journals Esophageal temperature monitoring during radiofrequency catheter ablation: experimental study based on an agar phantom model

2007 ◽  
Vol 28 (5) ◽  
pp. 453-463 ◽  
Author(s):  
Ignacio Rodríguez ◽  
Juan L Lequerica ◽  
Enrique J Berjano ◽  
Maria Herrero ◽  
Fernando Hornero
Keyword(s):  
Experimental Study ◽  
Catheter Ablation ◽  
Radiofrequency Catheter Ablation ◽  
Temperature Monitoring ◽  
Esophageal Temperature ◽  
Phantom Model

scholarly journals On the limitations of the applicability of Young’s equations temperature

2021 ◽  
Vol 23 (2) ◽  
pp. 218-222
Author(s):  
Magomed Pashevich Dokhov
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Interfacial Energy ◽  
Contact Angles ◽  
Surface Phenomena ◽  
Surface Energies ◽  
Three Phase ◽  
Production Techniques ◽  
The Difference ◽  
Solid Liquid

The article uses the thermodynamics of interfacial phenomena to justify the fact that Young’s equations can correctly describe the three-phase equilibrium with any type of interatomic bonds. Wetting, adhesion, dissolution, surface adsorption, and other surface phenomena are important characteristics, whichlargely determine the quality and durability of materials, and the development of a number of production techniques, including welding, soldering, baking of metallic and non-metallic powders, etc. Therefore, it is important to study them.Using experimental data regarding surface energies of liquids (melts) and contact angles available in the literature, we calculated the surface energies of many solid metals, oxides, carbides, and other inorganic and organic materials without taking into account the amount of the interfacial energy at the solid-liquid (melt) interface. Some researchers assumed that in case of an acute contact angle the interfacial energy is low. Therefore, they neglected it and assumed it to be zero.Others knew that this value could not be measured, that is why they measured and calculated the difference between the surface energy of a solid and the interfacial energy of a solid and a liquid (melt), which is equal to the product of the surface energy of this liquid by the cosine of the contact angle. It is obvious that these methods of determining the surface energy based on such oversimplified assumptions result in poor accuracy.Through the use of examples this paper shows how the surface energies of solids were previously calculated and how the shortcomings of previous calculations can be corrected

scholarly journals EXPERIMENTAL STUDY OF CONCRETE PERFORMANCE

2020 ◽  
Vol 2 (1) ◽  
pp. 48-61
Author(s):  
Sang Kee ◽  
Yuhee Park ◽  
Eun Choi
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Strength Test ◽  
The Other ◽  
Average Score ◽  
Two Samples ◽  
The Difference ◽  
B Test

This study was experimental in nature and conducted with the view to make comparison between two samples. The first sample consisted of concrete with rice husk ash mixed in it and the other sample was without such addition. The first test conducted to test the performance was simple measurements. The results show that for the sample without addition of rice husk ash, the density was 2355.97 and for included sample, the density was 2354.44 with insignificant differences (t-stat= 0.766, P>.05). For V-B test, the sample without addition of rice husk as was 8.34 and for include sample, it was 8.01. The differences for V-B for both samples were statistically insignificant (t-stat=1.431, P>.05). The slump test without for the sample without addition of rice husk was 12.75 and for included sample, it was 18.56. The difference was statistically significant (t-stat=2.455, P<.05). The compressive strength for excluded sample was 24.32 and for included sample was 20.01. The results were statistically insignificant (t-value= 1.13, P>.05). For flexural strength test, for excluded sample, the average score was 9.02 and for included sample, the average score was 9.19. The difference was statistically insignificant (t-stat=1.45, P>.05). Overall, the results lead to the conclusion that there are insignificant differences of addition of rice husk ash in concrete.

The Effect of Radiofrequency Catheter Ablation on Permanent Pacemakers: An Experimental Study

1990 ◽  
Vol 13 (1) ◽  
pp. 23-29 ◽  
Author(s):  
MICHAEL C. CHIN ◽  
MARTEN ROSENQVIST ◽  
MICHAEL A. LEE ◽  
JERRY C. GRIFFIN ◽  
JONATHAN J. LANGBERG
Keyword(s):  
Experimental Study ◽  
Catheter Ablation ◽  
Radiofrequency Catheter Ablation
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