A Theoretical and Experimental Analysis of Radiofrequency Ablation with a Multielectrode, Phased, Duty-Cycled System

Lau, Michael; Hu, Betty; Werneth, Randy; Sherman, Marshall; Oral, Hakan; Morady, Fred; Krysl, Petr

doi:10.1111/j.1540-8159.2010.02801.x

Cited by 20 publications

(16 citation statements)

References 26 publications

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“…First, at temperatures below 100ºC,  increases. However, there are discrepancies about the rate of this increase, from +1.5%/ºC [15] to +2%/ºC [8], and about the increase type, linear [16,17] or exponential [13,18]. 5 At temperatures above 100ºC vaporization occurs and desiccation implies a rapid drop of .…”

Section: Temperature-dependence Of Electrical Conductivity (mentioning

confidence: 99%

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Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Trujillo

Berjano

2013

International Journal of Hyperthermia

126

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Purpose: Although theoretical modeling is widely used to study different aspects of radiofrequency ablation (RFA) its utility is directly related to its realism. An important factor in this realism is the use of mathematical functions to model the temperaturedependence of tissue thermal (k) and electrical () conductivities. Our aim was to review the piecewise mathematical functions most commonly used for modeling the temperaturedependence of k and  in RFA computational modeling. Materials and methods:We built a hepatic RFA theoretical model of a cooled electrode and compared lesion dimensions and impedance evolution with combinations of mathematical functions proposed in previous studies We employed the thermal damage contour D63 to compute the lesion dimension contour, which corresponds to Ω= 1, Ω being local thermal damage assessed by the Arrhenius damage model. Results:The results were very similar in all cases in terms of impedance evolution and lesion size after 6 minutes of ablation. Although the relative differences between cases in terms of time to first roll-off (abrupt increase in impedance) were as much as 12%, the maximum relative differences in terms of the short lesion (transverse) diameter were below 3.5%. Conclusions:The findings suggest that the different methods of modeling temperature dependence of k and  reported in the literature do not significantly affect the computed lesion diameter.3

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Section: Temperature-dependence Of Electrical Conductivity (mentioning

confidence: 99%

“…Most RFA theoretical models have used a constant value for k [14,15,17,[20][21][22], probably due to the fact that changes in k with temperature are not so marked as in  [10,23].…”

Section: Temperature-dependence Of Thermal Conductivity (K)mentioning

confidence: 99%

Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Trujillo

Berjano

2013

International Journal of Hyperthermia

126

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“…The 2:1 setting gives more energy in unipolar mode which creates deeper lesions but with the possible risk of gaps between the poles. Several studies have reported a gradual increase in lesion depth by increasing the ratio of unipolar energy delivered by the PVAC [11][12]. Wijffels et al [11] reported that all energy setting (unipolar, 1:1, 2:1 and 4:1 bipolar/unipolar ratio) produces transmural lesions.…”

Section: Discussionmentioning

confidence: 99%

“…The energy can be delivered in a unipolar or bipolar setting or combined in various ratios. A higher proportion of unipolar energy will give deeper lesions but less energy between the poles possibly leading to non-continuous lines [12]. Although certain energy settings have been recommended for PV isolation there are no randomized…”

Section: Introductionmentioning

confidence: 99%

Efficacy and Safety of Different Energy Settings for Atrial Fibrillation Ablation using the Duty-cycled Radiofrequency Ablation Catheter (PVAC)

Lönnerholm¹

2014

J Cardiovasc Med Cardiol

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In recent years, new ablation catheters have been developed to facilitate atrial fibrillation (AF) ablation procedures, including the multi-electrode pulmonary vein ablation catheter (PVAC), capable of using different proportions of unipolar and bipolar energy. The purpose of this study was to evaluate the acute efficacy, as well as safety, when using the two different energy settings for the PVAC catheter. Methods and Results:Thirty-five patients with a mean age of 62 ± 7.7 years with paroxysmal (54%) or persistent AF were included in the study and randomized to 4:1 versus 2:1 bipolar/unipolar energy setting with the PVAC device. The mean number of applications with the PVAC catheter was 41 ± 10 and 51 ± 15 (p = 0.3) respectively with the 4:1 and the 2:1 setting. Touch-up with another RF ablation catheter was necessary in 3 and 7 patients respectively in the 4:1 and 2:1 group. The procedure time was 155 ± 35 and 174 ± 41minutes respectively and the total fluoroscopy time, including the time for touch-up with another catheter, was 42 ± 14 and 50 ± 17 minutes respectively with the 4:1 versus 2:1 setting. No complications were seen in any group. Conclusion:There was no significant difference between the 4:1 and 2:1 bipolar-tounipolar energy setting with the PVAC regarding the number of applications needed to create (PVI), the number of patients in which (PVI) could be achieved without touch-up applications, the procedure time or the fluoroscopy time. studies that have compared the different settings for this purpose. The aim of this study was therefore to compare the efficacy and safety of PV isolation using a 4:1 versus a 2:1 unipolar/bipolar energy setting with the PVAC. Our hypothesis was that the 2:1 setting, delivering more unipolar energy, would result in deeper and more transmural lesions for pulmonary vein isolation leading to fewer applications and thus shorter procedure times. Methods PatientsThe patients included in this single-center study was a subset of patients in a larger randomized study comparing the PVAC and the CryoCath cryo-balloon (both Medtronic; Minneapolis, MN, USA) and were included between

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“…1. An advanced balloon catheter design with multiple sensors on the outside surface was reported for enabling the catheter to obtain temperature, flow characteristics, tactile, optical, and electrophysiological data from the tissue-balloon interface [17][18][19][20][21][22][23][24][25][26][27][28]. While the CA is considered as one of the best methods for diagnosing and treating AF, there is a higher risk of procedural complications due to the complexity of technique and the location of ablation sites [5].…”

Section: Introductionmentioning

confidence: 99%

A review: flexible, stretchable multifunctional sensors and actuators for heart arrhythmia therapy

Kang¹,

Pak

2017

Micro and Nano Syst Lett

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Cardiovascular disease is a very serious disease which results in about 30% of all global mortality. Atrial fibrillation (AF) causes rapid and irregular contractions resulting in stroke and cardiac arrest. AF is caused by abnormality of the heartbeat controlling electrical signal. Catheter ablation (CA) is often used to treat and remove the abnormal electrical source from the heart but it has limitations in sensing capability and spatial coverage. To overcome the limitations of the CA, new devices for improving the spatial capability have been reported. One of the most impressive methods is wrapping the heart surface with a flexible/stretchable film with an array of high-density multifunctional micro-sensors and actuators. With this technique, the overall heart surface may be diagnosed in real time and the AF may be treated much more effectively. The data acquisition from the array of multifunctional sensors is also very important for making the new devices useful. To operate the implanted device system, a battery is mostly used and it should be avoided to replace the battery by surgery. Therefore, various energy harvesting techniques or wireless energy transfer techniques to continuously feed the power to the system are under investigation. The development of these technologies was reviewed, and the current level of technology was reviewed and summarized.

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A Theoretical and Experimental Analysis of Radiofrequency Ablation with a Multielectrode, Phased, Duty-Cycled System

Cited by 20 publications

References 26 publications

Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Efficacy and Safety of Different Energy Settings for Atrial Fibrillation Ablation using the Duty-cycled Radiofrequency Ablation Catheter (PVAC)

A review: flexible, stretchable multifunctional sensors and actuators for heart arrhythmia therapy

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