Optimal lesion size index to prevent conduction gap during pulmonary vein isolation

Kanamori, Naomi; Kato, Takeshi; Sakagami, Satoru; Saeki, Takahiro; Kato, Chieko; Kawai, Keiichi; Chikata, Akio; Takashima, Shinya; Murai, Hisayoshi; Usui, Soichiro; Furusho, Hiroshi; Kaneko, Shuichi; Takamura, Masayuki

doi:10.1111/jce.13727

Cited by 44 publications

(62 citation statements)

References 19 publications

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“…When we deliver high power RF applications in the atrium, we need to be sure to create adequate lesions to achieve a PV isolation, and not to overheat the tissue, to avoid any complications. The AI and LSI have been established as parameters for evaluating the lesion quality and are widely accepted in PV isolation . The knowledge of the tissue thermodynamics with different power settings based on the AI/LSI would be important to create adequate lesions and to determine the RF power settings for use in the clinical situation.…”

Section: Discussionmentioning

confidence: 99%

“…The RF applications were performed using a ThermoCool SmartTouch SF catheter with the SMARTABLATE RF Generator (Biosense Webster Inc., Diamond Bar, CA) and TactiCath SE catheter with the Ampere RF Generator (Abbott, St. Paul, MN) with a 10 to 12 g contact force until the AI or LSI reached the target value. The target AI value was 350 and the target LSI value was 4.5, which are used for the LA posterior wall in clinical practice . The angle of the ablation catheter was kept at 45° from the tissue.…”

Section: Methodsmentioning

confidence: 99%

“…The AI and LSI have been reported to be superior for predicting the lesion size than the force time integral . Several clinical studies have shown the utility of the AI/LSI during the PVI . Theoretically, a similar ablation lesion size can be created under the same RF index (AI or LSI) even though the RF power settings differ (high and low power).…”

Section: Introductionmentioning

confidence: 99%

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Different tissue thermodynamics between the 40 W and 20 W radiofrequency power settings under the same ablation index/lesion size index

Takemoto

Takami

Fukuzawa

et al. 2019

Cardiovasc electrophysiol

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Introduction:The ablation index (AI) and lesion size index (LSI) are novel markers for predicting the ablation lesion quality, however, collateral damage is still a concern.This study aimed to compare the lesion characteristics and tissue temperature profiles between 20 W (20 Ws) and 40 W (40 Ws) ablation settings under the same AI and LSI.Methods: An ex vivo model consisting of swine myocardium (5-6 mm thickness) in a circulating, warmed saline bath was used. Twenty-one tissue temperature electrodes were used. Radiofrequency applications with different power settings were performed with a 10 to 12 g contact force until the AI and LSI reached 350 and 4.5, respectively.Results: A total of 120 radiofrequency (RF) applications and 2520 tissue temperature profiles were analyzed. The speed of the tissue temperature rise with 40 Ws was significantly faster than that with 20 Ws. However, the maximum tissue temperature did not significantly differ between 20 and 40 Ws with the same AI (44.6°C ± 3.9°C vs 45.1°C ± 6.4°C, P = .73), and was significantly lower for 40 Ws with the same LSI (42.8°C ± 3.4°C vs 40.0°C ± 3.4°C, P = .003). For both the AI and LSI, the number of electrodes exhibiting high temperatures (≥39°C) was significantly larger and the duration of high tissue temperatures was significantly longer with 20 Ws. The thermal latency with 40 Ws was greater.Conclusions: Although the targeted AI and LSI were the same for both 20 and 40 Ws, the tissue temperature profiles differed greatly depending on the RF power setting. A high power setting based on the AI and LSI may reduce the collateral thermal damage. K E Y W O R D S ablation index, catheter ablation, lesion size index, tissue thermodynamics 1 | INTRODUCTION Pulmonary vein isolation (PVI) is a cornerstone of radiofrequency (RF) catheter ablation of atrial fibrillation. Transmural and continuous ablation lesions are essential factors for preventing reconduction of the PVs, however, an excessive contact force and overheating of the tissue can cause steam pops, cardiac perforations, and collateral damage. Low power long duration RF settings (20-25 W × 20-30 seconds) have been used for the posterior wall of the left atrium (LA) especially in areas adjacent to the esophagus.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Different tissue thermodynamics between the 40 W and 20 W radiofrequency power settings under the same ablation index/lesion size index

Takemoto

Takami

Fukuzawa

et al. 2019

Cardiovasc electrophysiol

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“…Unilateral femoral-venous access was performed for PVAC/cryoballoon and bilateral for 3D-RF cases. Duration of 3D-RF application was determined by Force-Time-Integral [ 10 ], Lesion-Size-Index [ 11 ] or Ablation-Index [ 12 ]. A transthoracic echocardiogram (TTE) was performed in all immediately post-procedure with repeat 2-3 h later; protamine 50 mg was administered post-op and femoral haemostasis achieved using digital manual pressure or a ‘figure-of-8’ (Z) suture [ 13 ] using the same-day protocol.…”

Section: Methodsmentioning

confidence: 99%

Safety and cost-effectiveness of same-day complex left atrial ablation

Datla

Weight

et al. 2021

International Journal of Cardiology

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Background Catheter ablation for complex left-atrial arrhythmia is increasing worldwide with many centres admitting patients overnight. Same-day procedures using conscious sedation carry significant benefits to patients/healthcare providers but data are limited. We evaluated the safety and cost-effectiveness of same-day complex left-atrial arrhythmia ablation. Method Multi-centre retrospective cohort study of all consecutive complex elective left-atrial ablation procedures performed between January 2011 and December 2019. Data were collected on planned same-day discharge versus overnight stay, baseline parameters, procedure details/success, ablation technology, post-operative complications, unplanned overnight admissions/outcomes at 4-months and mortality up to April 2020. A cost analysis of potential savings was also performed. Results A total of 967 consecutive patients underwent complex left-ablation using radiofrequency (point-by-point ablation aided by 3D-mapping or PVAC catheter ablation with fluoroscopic screening) or cryoballoon-ablation (mean age: 60.9 ± 11.6 years, range 23-83 yrs., 572 [59%] females). The majority of patients had isolation of pulmonary veins alone ( n = 846, 87%) and most using conscious-sedation alone ( n = 921, 95%). Of the total cohort, 414 (43%) had planned same-day procedure with 35 (8%) admitted overnight due to major ( n = 5) or minor ( n = 30) complications. Overall acute procedural success-rate was 96% ( n = 932). Complications in planned overnight-stay/same-day cohorts were low. At 4-month follow-up there were 62 (6.4%) readmissions (femoral haematomas, palpitation, other reasons); there were 3 deaths at mean follow-up of 42.0 ± 27.6 months, none related to the procedure. Overnight stay costs £350; the same-day ablation policy over this period would have saved £310,450. Conclusions Same-day complex left-atrial catheter ablation using conscious sedation is safe and cost-effective with significant benefits for patients and healthcare providers. This is especially important in the current financial climate and Covid-19 pandemic.

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“…Preliminary evidence suggests that lesions delivered with this approach may have improved transmurality and linear contiguity. Criteria for effective individual lesions include documenting a fall in impedance (eg, ≥8‐10 Ω), reductions in electrogram amplitude, loss of negativity on the unipolar electrogram, loss of pacing capture at the ablation site and ablation indices that incorporate power, duration, and contact force …”

Section: Considerations For Effective Ablationmentioning

confidence: 99%

Approach to catheter ablation of left atrial flutters

Markowitz

Thomas

Liu

et al. 2019

Cardiovasc electrophysiol

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Left atrial tachycardias (ATs) most commonly occur after catheter or surgical ablation of atrial fibrillation and in patients with atrial myopathies. Pre‐existing scar in the left atrium (LA) can result in complex circuits, sometimes with narrow channels that can be detected with high‐resolution mapping. The most common forms of macroreentrant AT from the LA are variants of peri‐mitral and roof‐dependent reentry. Localized reentrant rhythms occur in the setting of fibrosis that gives rise to slow conduction and may occur adjacent to areas of prior ablation. The approach to treating these ATs involves first identifying the left atrial origin, defining the tachycardia circuit – which can be facilitated by ultrahigh density mapping and entrainment – and selecting a suitable isthmus to target for ablation. An important endpoint in ablating left atrial flutters is to establish and confirm bidirectional line of the block. Challenges in ablating these ATs include the presence of multiple tachycardias, defining circuits with complex activation patterns and achieving durable lines of block, particularly in the lateral mitral isthmus. Progress in treating these arrhythmias has come from new mapping technologies and the recognition of epicardial connections that allow for persistent conduction across ablation lesions. Also, advances in delivering energy to obtain complete transmural lesions promise to improve the long‐term success of ablating ATs from the LA.

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Optimal lesion size index to prevent conduction gap during pulmonary vein isolation

Abstract: The LSI can be used to predict gaps/DC during the PVI procedure. An LSI of 5.2 may be a suitable target for effective lesion formation. An LSI of 4.0 may be acceptable in the posterior wall, especially in areas adjacent to the esophagus.

Cited by 44 publications

References 19 publications

Different tissue thermodynamics between the 40 W and 20 W radiofrequency power settings under the same ablation index/lesion size index

Different tissue thermodynamics between the 40 W and 20 W radiofrequency power settings under the same ablation index/lesion size index

Safety and cost-effectiveness of same-day complex left atrial ablation

Approach to catheter ablation of left atrial flutters

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