The Effective Contact Force to Minimize Edema Relative to Chronic Lesion Formation During Radiofrequency Ablation in Ventricular Wall

Yamashita, Kennosuke; Ghafoori, Elyar; Silvernagel, Josh; Ashton, John H.; Dosdall, Derek J.; MacLeod, Robert S.; Ranjan, Ravi

doi:10.1536/ihj.19-128

Cited by 4 publications

(4 citation statements)

References 18 publications

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“…In this experiment, as in previous reports, there was no significant difference in either depth or surface area with increasing CF for a short duration of 15 s. 11 However, the lesions became larger as the CF increased when the contact angle was perpendicular and the duration was >30 s. Although the difference was not significant in the cases with parallel contact, the depth and surface area were always greater when the CF was 30 g than when it was 10 g. These results suggest that CF may influence the lesion size even with DTA if the energization duration is ≥30 s, as previously reported for CF‐sensing ablation catheters. 5 , 6 , 7 , 8 , 13 , 14 …”

Section: Discussionmentioning

confidence: 99%

The effect of ablation settings on lesion characteristics with DiamondTemp ablation system: An ex vivo experiment

Nomura,

Maeda,

Kumazawa

et al. 2023

Journal of Arrhythmia

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IntroductionCreating large lesion in ablations using the DiamondTemp (DTA) ablation system may reduce the frequency of arrhythmia recurrence and allow the treatment of ventricular arrhythmias. Therefore, this study aimed to investigate whether power, application time, contact force (CF), and contact angle affect lesion formation in the ventricles.MethodsAblations were delivered to porcine myocardial preps to evaluate the lesion characteristics. Ablations were conducted with a maximum power of 50 W, target temperature of 58°C, CF of 10, 20, or 30 g, and contact angle between the catheter tip and tissue. The ablation durations were 15, 30, 60 s, 15 s × 2, or 30 s × 2.ResultsSteam pops occurred only in cases with perpendicular contact. The lesion depth was larger in all settings in the perpendicular orientation than in the parallel orientation. The temperatures were lower in all settings in the perpendicular orientation than in the parallel orientation. The lesions became larger as CF increased with perpendicular contact and duration of ≥30 s. The longer application time resulted in larger surface area, depth, and volume of the lesion. Lesion depth was greater with single application of 30 and 60 s than with 15 s × 2 and 30 s × 2, respectively.ConclusionIt is important to perform a single prolonged application as much as possible to create deeper lesions. Parallel contact with the tissue should be maintained to take advantage of the temperature sensor's capabilities to avoid pop phenomenon.

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Section: Discussionmentioning

confidence: 99%

The effect of ablation settings on lesion characteristics with DiamondTemp ablation system: An ex vivo experiment

Nomura,

Maeda,

Kumazawa

et al. 2023

Journal of Arrhythmia

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“…This suggests a greater degree of edema in the LV free wall compared to other locations. A possible explanation to this finding is that higher strain and contractile forces in the LV could lead to higher degrees of edema ( 14 ).…”

Section: Discussionmentioning

confidence: 99%

“…This decrease in lesion size is mainly explained by the subsiding edema and inflammation over time. Edema formation can be minimized by increasing contact force (> 12.5 g according to latest literature) ( 14 ). This phenomenon helps explain the dynamic evolution of the scar and can be monitored during catheter ablation procedure.…”

Section: Discussionmentioning

confidence: 99%

Predictors of Lesions Contiguity and Transmurality in Canine Ventricular Models After Catheter Ablation

Hajjar

Mekhael

Huang

et al. 2022

Front. Cardiovasc. Med.

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BackgroundInterlesion gaps and transmurality of lesions after catheter ablation can precipitate suboptimal efficacy in preventing arrhythmias.AimsWe aim to assess predictors of acute transmural lesion formation and the interlesion distance threshold for creating a continuous, chronic scar after ventricular ablation.Materials and MethodsAblation procedures were performed on 7 canines followed by late gadolinium enhancement MRI (LGE-MRI). Transmurality of lesions was assessed by 2 independent operators. Ablation parameters such as duration (s), power (W), temperature (C), contact force (CF) (g), were collected for each ablation point. After 7-12 weeks, LGE-MRI was performed, followed by euthanasia, and heart excision. Some lesions were created in pair. Lesion pairs were spaced 7-21 mm apart as measured by Electroanatomic mapping (EAM), with different operating parameters (power 35 or 50W, duration of energy delivery 10, 20 or 30s and contact force of 10g or above). We performed a logistic regression analysis to determine predictors of transmural lesion formation.ResultsEighty-one radiofrequency ablation were performed in total [33 in the Left ventricle (LV) and 48 in the Right ventricle (RV)]. Higher CF was a significant predictor of transmural lesion formation (β = 0.15, OR = 1.16, 95% CI [1.03 – 1.3], p = 0.01), and lesions delivered in the RV were more frequently transmural than lesions delivered in the LV (β = −2.43, OR = 0.09, 95%CI [0.02 – 0.34], p < 0.001). For the paired analysis, thirty-eight lesions were created contiguously: fourteen connected lesions and twenty-four unconnected lesions. EAM distance was significantly larger in unconnected lesions than connected lesions (16.17 ± 0.92 mm vs. 11.51 ± 0.68 mm, respectively, p < 0.05). We concluded that an interlesion distance of less than 10 mm is required to prevent gap formation. Average volumes in unconnected lesions (n = 24) at the acute and chronic stages were 0.55 ± 0.11 cm3 and 0.20 ± 0.02 cm3, respectively. On average, lesion volumes were 64% (p < 0.05) smaller at the chronic stage compared to the acute stage. Among connected lesions (n = 14), we observed a volume of 1.19 ± 0.8 cm3 and 0.39 ± 0.15 cm3 at the acute and chronic stages, respectively. These connected lesions reduced in volume by 67% on average.ConclusionTo create contiguous scars on the ventricular endocardial surface, paired lesions should be spaced less than ten millimeters apart. Higher contact force should be used in ventricular ablation to create transmural lesions.

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“…It is possible that changes in tissue thickness post-ablation may vary depending on the amount of force applied as shown in the ventricles in animal models. 30 Further studies are needed to evaluate this relationship.…”

Section: Limitationsmentioning

confidence: 99%

Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies

Gao

Chang²,

Bilchick

et al. 2021

Cardiovasc electrophysiol

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Introduction: Thermally induced cardiac lesions result in necrosis, edema, and inflammation. This tissue change may be seen with ultrasound. In this study, we sought to use intracardiac echocardiography (ICE) to evaluate pulmonary vein tissue morphology and assess the acute tissue changes that occur following radiofrequency (RF) or laser ablation for atrial fibrillation (AF).Methods and Results: Patients with AF underwent pulmonary vein isolation (PVI) using irrigated RF or laser balloon. Pre-and post-ablation ICE imaging was performed from within each pulmonary vein (PV). At least 10 transverse imaging planes per PV were evaluated and each plane was divided into eight segments. The PV/ atrial wall thickness and the luminal area were measured at each segment. Twentyseven patients underwent PVI (15 with laser, 12 with RF). Ninety-eight pulmonary veins were analyzed (58 PVs laser; 40 PVs RF). At baseline, there were no regional differences in PV wall thickness in the right-sided veins. The anterior regions of left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) were significantly thicker compared with the posterior and inferior regions (p < .01). Postablation, PV wall thickness in RF group increased 24.1% interquartile range (IQR) (17.2%-36.7%) compared with 1.2% IQR (0.4%-8.9%) in laser group, p = .004. In all PVs, RF ablation resulted in significantly greater percent increase in wall thickness compared with laser. Additionally, RF resulted in more variable changes in regional PV wall thickness; with more increases in wall thickness in anterior versus posterior LSPV (75.4 ± 58.5% vs. 46.8 ± 55.6%, p < .01), anterior versus posterior right superior pulmonary vein (RSPV) (62.9 ± 63.9% vs. 44.6 ± 51.7%, p < .05), and superior versus inferior RSPV (69.1 ± 45.4% vs. 35.9 ± 45%, p < .05). There were no significant regional differences in PV wall thickness changes for the laser group.Conclusions: Rotational ICE can be used to measure acute tissue changes with ablation. Regional variability in baseline wall thickness was nonuniformly present in PVs. Acute tissue changes occurred immediately post-ablation. Compared with laser How to cite this article: Gao X, Chang D, Bilchick K, et al. Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: laser versus radiofrequency energies.

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The Effective Contact Force to Minimize Edema Relative to Chronic Lesion Formation During Radiofrequency Ablation in Ventricular Wall

Cited by 4 publications

References 18 publications

The effect of ablation settings on lesion characteristics with DiamondTemp ablation system: An ex vivo experiment

The effect of ablation settings on lesion characteristics with DiamondTemp ablation system: An ex vivo experiment

Predictors of Lesions Contiguity and Transmurality in Canine Ventricular Models After Catheter Ablation

Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies

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