Effect of catheter movement and contact during application of radiofrequency energy on ablation lesion characteristics

Olson, Matthew D.; Phreaner, Nicholas; Schuller, Joseph L.; Nguyen, Duy T.; Katz, David F.; Aleong, Ryan G.; Tzou, Wendy S.; Sung, Raphael K.; Varosy, Paul D.; Sauer, William H.

doi:10.1007/s10840-013-9824-4

Cited by 49 publications

(41 citation statements)

References 17 publications

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“…This ex vivo model has been validated and described in further detail elsewhere. 8,9 A 4-mm nonirrigated radiofrequency ablation catheter (Biosense-Webster, Diamond Bar, CA) was positioned with 10 g of force in a perpendicular position using a deflectable sheath (Agilis; St. Jude Medical, St Paul, MN).…”

Section: See Editorial By Hainesmentioning

confidence: 99%

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles

Nguyen¹,

Tzou²,

Zheng³

et al. 2016

Circ: Arrhythmia and Electrophysiology

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Background-Remote heating of metal located near a radiofrequency ablation source has been previously demonstrated.Therefore, ablation of cardiac tissue treated with metallic nanoparticles may improve local radiofrequency heating and lead to larger ablation lesions. We sought to evaluate the effect of magnetic nanoparticles on tissue sensitivity to radiofrequency energy. Methods and Results-Ablation was performed using an ablation catheter positioned with 10 g of force over prepared ex vivo specimens. Tissue temperatures were measured and lesion volumes were acquired. An in vivo porcine thigh model was used to study systemically delivered magnetically guided iron oxide (FeO) nanoparticles during radiofrequency application. Magnetic resonance imaging and histological staining of ablated tissue were subsequently performed as a part of ablation lesion analysis. Ablation of ex vivo myocardial tissue treated with metallic nanoparticles resulted in significantly larger lesions with greater impedance changes and evidence of increased thermal conductivity within the tissue. Magnet-guided localization of FeO nanoparticles within porcine thigh preps was demonstrated by magnetic resonance imaging and iron staining. Irrigated ablation in the regions with greater FeO, after FeO infusion and magnetic guidance, created larger lesions without a greater incidence of steam pops. Conclusions-Metal nanoparticle infiltration resulted in significantly larger ablation lesions with altered electric and thermal conductivity. In vivo magnetic guidance of FeO nanoparticles allowed for facilitated radiofrequency ablation without direct infiltration into the targeted tissue. Further research is needed to assess the clinical applicability of this ablation strategy using metallic nanoparticles for the treatment of cardiac arrhythmias. (Circ Arrhythm Electrophysiol. 2016;9:e003820.

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Section: See Editorial By Hainesmentioning

confidence: 99%

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles

Nguyen¹,

Tzou²,

Zheng³

et al. 2016

Circ: Arrhythmia and Electrophysiology

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“…An ex vivo model was used, as previously validated and described in detail elsewhere. 9,10 In brief, viable bovine myocardium was placed on top of a submersible load cell in a circulating saline bath at 371C. Fluid was circulated in a saline bath at a rate of 5 L/ min using a perfusion pump designed for cardiac bypass.…”

Section: Ex Vivo Modelmentioning

confidence: 99%

Effects of radiofrequency energy delivered through partially insulated metallic catheter tips on myocardial tissue heating and ablation lesion characteristics

Nguyen¹,

Moss²,

Zheng³

et al. 2015

Heart Rhythm

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“…2 While constant contact is desirable, higher forces may be potentially hazardous if the median forces exceed 60 g. 3 It is recognized that catheter-tissue contact forces (CFs) will vary in the beating heart and during respiration. 4 The CF-time integral (FTI) has been employed as an end point to account for this variability and inform successful lesions within the left atria. The FTI reflects duration (in seconds) of the average CF during radiofrequency (RF) application.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Ranges of Contact Force During Radiofrequency Ablation

Boles¹,

Enríquez²,

Riegert³

et al. 2016

JICRM

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ABSTRACT. The aim was to assess the dynamic range for contact force (CF df ) in order to achieve an effective lesion according to anatomic variables under conscious sedation. We retrospectively studied 674 radiofrequency (RF) lesions (21 procedures) at Kingston General Hospital. Consecutive patients employing a CF catheter were recruited. A force-sensing catheter was used to continuously record CF data and force-time integral (FTI) during each lesion. The CF df represents the difference between the highest and lowest recorded contact force for each RF application. Out of 674 lesions examined, we included 438 (65%). The CF df was significantly greater in the left atrium than in the right (36.6±20.3 versus 28.7±16.4, po0.01). Except in the cavotricuspid isthmus, the FTI lesions equal or are more than 400 g/s required higher CF df in all anatomical locations, and these differences reached statistical difference on the right atrial free wall, left atrial posterior wall, and right pulmonary vein antrum (p ¼ 0.011, 0.007, and o0.001). Yet, higher CF df is an independent predictor for less successful lesions in stepwise regression model. Left atrial enlargement above 46 mm was associated with lower CF df , CF av , and CF max (p ¼ 0.04, o0.001, and 0.02 respectively). This study represents the first detailed assessment of CF df in conscious sedation patients. Significant variations in the CF df were associated with different anatomic locations. We found that the greater the dynamic range the less likely the lesion would reach 400 g/s. Smaller atria were associated with higher dynamic ranges and greater peak and average forces.KEYWORDS. Average contact force, dynamic range for contact force, force time integral, maximum contact force, radiofrequency ablation.

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Effect of catheter movement and contact during application of radiofrequency energy on ablation lesion characteristics

Abstract: In our ex vivo model, externally irrigated radiofrequency catheters produced drag lesion volumes equal to or larger than those created by a point-by-point method.We also found decreased lesion size due to intermittent contact can be overcome by increasing duration of ablation time.

Cited by 49 publications

References 17 publications

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles

Effects of radiofrequency energy delivered through partially insulated metallic catheter tips on myocardial tissue heating and ablation lesion characteristics

Dynamic Ranges of Contact Force During Radiofrequency Ablation

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