A novel radiofrequency ablation catheter using contact force sensing: Toccata study

doi:10.1016/j.hrthm.2011.08.021

Heart Rhythm

Volume 9, Issue 1, January 2012, Pages 18-23

https://doi.org/10.1016/j.hrthm.2011.08.021 Get rights and content

Objectives

The aim of this multicenter study was to evaluate the device- and procedure-related safety of a novel force-sensing radiofrequency (RF) ablation catheter capable of measuring the real-time contact force (CF) and to present CF data and its possible implications on patient safety.

Background

The clinical outcome of RF ablation for the treatment of cardiac arrhythmias may be affected by the CF between the catheter tip and the tissue. Insufficient CF may result in an ineffective lesion, whereas excessive CF may result in complications.

Methods

Seventy-seven patients (43 with right-sided supraventricular tachycardia [SVT] and 34 with atrial fibrillation [AF]) received percutaneous ablation with the novel studied catheter. The CF applied and safety events related to the procedure were reported.

Results

CF values at mapping ranged from 8 ± 8 to 60 ± 35 g and from 12 ± 10 to 39 ± 29 g in the SVT group and the LA group, respectively, showing a significant interinvestigator variability (P < .0001). High transient CFs (>100 g) were noted in 27 patients (79%) of the LA group. One device-related complication (tamponade, 3%) occurred in the AF group.

Conclusions

Catheter ablation using real-time CF technology is safe for the treatment of SVT and AF. High CFs may occur during catheter manipulation and not just during ablation, suggesting that measuring CF may provide additional useful information to the operator for safe catheter manipulation. In the future, CF-sensing catheters may also increase the effectiveness of RF ablations by allowing better control of the RF lesion size.

Introduction

Over the past 2 decades, percutaneous catheter ablation has become the most common treatment of recurrent supraventricular tachycardias (SVTs), such as atrioventricular nodal reentry tachycardia (AVNRT), accessory pathway Wolff–Parkinson–White syndrome,1, 2 atrial flutter, and other atrial tachycardias.2, 3 Radiofrequency (RF) catheter ablation of atrial fibrillation (AF) is increasingly commonly performed, and the various techniques for ablation in the left atrium (LA) include, at minimum, electrical isolation of the pulmonary veins (PVs).¹

Recent preclinical research has shown that the contact force (CF) between the catheter tip and the target tissue is a key factor to safe and effective lesion formation.4, 5 Insufficient CF may result in an ineffective lesion, whereas excessive CF may result in complications such as heart wall perforation, steam pop, thrombus formation, or esophageal injury.5, 6, 7, 8, 9 Until now, the operator could assess the CF only indirectly, or with a force sensor available with a robotic system at the proximal end of a sheath.¹⁰ To allow continuous, accurate, and direct measurement of the CF between the catheter tip and the target tissue, a novel technology was developed that integrates a CF sensor at the distal tip of an RF open-irrigated catheter.⁵ The objective of this paper was to evaluate the clinical data of a novel CF-sensing open-irrigated tip RF ablation catheter in terms of both device-related and procedure-related safety up to 12 months postprocedure and to present CF data during the interventional procedure and its possible implications on patient safety. Knowledge of the CF may reduce commonly related complications.

Section snippets

Patients

This study enrolled 2 patient groups with atrial arrhythmias. The right-sided SVT group consisted of patients with confirmed right-sided SVT that included AVNRT, Wolff–Parkinson–White syndrome, atrial tachycardia, and isthmus-dependent atrial flutter. The AF group consisted of patients with confirmed paroxysmal AF. A total of 77 Caucasian patients were enrolled in the study: 43 in the right-sided SVT group and 34 in the AF group. All study patients signed an informed consent form and met all

Right-sided SVT group

After diagnostic CF mapping, RF ablation was determined as contraindicated in 1 patient with AVNRT but with atypical atrioventricular node anatomy, and thus the patient was not ablated with the study device. A total of 42 patients (27 patients with atrial flutter, 13 patients with AVNRT, and 2 patients with Wolff–Parkinson–White syndrome) underwent the full study procedure and were evaluated at 7-day follow-up. During the further study follow-up, 3 patients withdrew consent. Patient

Discussion

This is the first clinical study measuring CF in real time during mapping and RF ablation of right-sided SVTs and AF. Knowledge of the CF during the interventional procedure may reduce commonly related complications and increase patient safety.

The safety profile of the CF catheter when used by the experienced investigators in this study was comparable to that of conventional irrigated RF catheters. The incidence of device- or procedure-related SAEs among study patients with right-sided SVT was

Conclusions

In conclusion, the CF catheter is as safe as conventional irrigated RF catheters. Assessment of CF showed marked inter- and intrainvestigator variability. High CF values may occur during manipulation and not just during ablation. This suggests that the ability to measure CF may provide additional useful information to the operator for safe catheter manipulation. In the future, CF-sensing catheters may increase the safety and effectiveness of RF ablation procedures by preventing the use of

Acknowledgments

The Data Safety and Monitoring Board members were Dr Hein Wellens (chair), Dr Riccardo Cappato, and Dr Christoph Geller. Editorial assistance in the preparation of this manuscript was provided by Mme Yvonne Moussy. Contact force was analyzed by Oriol Lluch Parellada from the Engineering Department of the Ecole Polytechnique Fédérale, Lausanne (EPFL), Switzerland.

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This study (NCT-03906461) was designed to capture best practices using LSI-guided catheter ablation to treat PAF subjects in a real-world setting.
This prospective single-arm observational study enrolled 143 PAF subjects in the United States, Europe, and Japan undergoing de novo PVI with RF ablation. PVI lesions were assigned to 10 anatomically defined segments. Mean LSIs achieved for all lesions were analyzed. Follow-up was conducted between 3–6 months and 12 months after the procedure.
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LSI-guided ablation strategies proved safe and effective despite differences in LSI workflows. Use of high LSI values resulted in shorter procedure, RF, and fluoroscopy times and fewer touch-up ablations compared to low LSI.
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A novel catheter technology (direct sense, DS) enables periprocedural local impedance (LI) measurement for estimation of tissue contact during radiofrequency ablation (RFA) for real-time assessment of lesion generation. This measure reflects specific local myocardial conduction properties in contrast to the established global impedance (GI) using a neutral body electrode. Our study aimed to assess representative LI values for the cardiac chambers, to evaluate LI drop in response to RF delivery and to compare those values to established GI measures in patients undergoing RFA procedures.
Seventy-three patients undergoing RFA with the DS technology were included. Within the cardiac chambers, baseline LI was significantly different, with the highest values in the left atrium (LA 107.5 ± 14.3 Ω; RV 104.6 Ω ± 12.9 Ω; LV 100.7 Ω ± 11.7 Ω, and RA 100.5 Ω ± 13.4 Ω). Baseline LI was positively correlated to the corresponding LI drop during RF delivery (R² = 0.26, p = 0.01) representing a promising surrogate of lesion generation. The observed mean LI drop (15.6 ± 9.5 Ω) was threefold higher as GI drop (4.9 ± 7.4 Ω), p < 0.01. We evaluated the clinical outcome in a subgroup of patients undergoing DS-guided pulmonary vein isolation, which was comparable regarding arrhythmia recurrence to a conventional ablation cohort (57 % vs 50 %, p = 0.2).
We provide detailed information on LI measures in electrophysiological procedures with significant differences within the cardiac chambers highlighting that RFA-related LI drop can serve as a promising surrogate for real-time assessment of lesion generation. Guiding the electrophysiologist in RFA procedures, this additional information promises to improve safety profile and success rates in the interventional treatment of arrhythmias.
Local impedance-guided ablation and ultra-high density mapping versus conventional or contact force-guided ablation with mapping for treatment of cavotricuspid isthmus dependent atrial flutter
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– Local impedance (LI) guided ablation as a method of judging lesion effectiveness for cavotricuspid isthmus dependent atrial flutter (CTI-AFL), and ultra-high density (UHD) mapping when breakthrough occurred across an ablation line has not previously been assessed.
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– The use of LI during ablation for real-time lesion assessment was as efficacious as the conventional and CF methods. UHD mapping rapidly identified breakthrough, including EEB.
Safety and Effectiveness of a Next-Generation Contact Force Catheter: Results of the TactiSense Trial
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Catheter ablation of atrial fibrillation (AF) is an established therapy for the treatment of PAF. Ablation technology is evolving with the primary goals of improving efficacy and safety of the procedure.
This was a multicenter single-arm trial evaluating a novel ablation catheter for the treatment of PAF. A total of 156 subjects were enrolled at 19 sites in the United States, Europe, and Australia. The primary safety endpoint was the rate of device- or procedure-related serious adverse events occurring within 7 days. The primary effectiveness endpoint was acute success defined as pulmonary vein isolation at 30 min after ablation. Two descriptive endpoints were prospectively captured: 1) 1-year freedom from recurrence of symptomatic AF, atrial flutter (AFL), and atrial tachycardia (AT) lasting ≥30 s without a new or increased dose of Class I/III antiarrhythmic drugs; and 2) 1-year drug-free success defined by the absence of any recurrent AF/AFL/AT lasting ≥30 s without using Class I/III antiarrhythmic drugs.
Primary safety events occurred in 4.7% of patients (95% confidence interval [CI]: 2.23% to 8.64%), and the procedure was acutely successful in 98.0% of patients (95% CI: 94.95% to 99.46%). According to Kaplan-Meier estimates at 1 year, 82.2% (95% CI: 74.7% to 87.6%) were free from symptomatic recurrence, and 1-year drug-free success was 68.2% (95% CI: 59.9% to 75.1%).
The TactiCath™ Contact Force Ablation Catheter, Sensor Enabled™ is safe and effective for the treatment of paroxysmal AF.
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Citation Excerpt :
Such heterogeneity in procedural techniques can confound the results of CA studies and can reduce applicability to later ablative efforts. Advances in 3-dimensional mapping, adoption of force-sensing catheters20,21 as well as the advent of alternatives to radiofrequency, notably cryoballoon technology,22 have resulted in more efficient and safer procedures. For patients with HF, complex CA procedures can be limited by the time under sedation and the need to limit fluid administration.
Atrial Fibrillation (AF) and heart failure (HF) with reduced ejection fraction (HFrEF) frequently coexist, resulting in significant morbidity and mortality. Therapeutic options for patients with AF and HFrEF are limited due to few antiarrhythmic drug (AAD) choices and historically equivocal effects of procedural interventions on mortality. However, recent randomized trials examining catheter ablation (CA) in AF patients with HFrEF have shown a beneficial effect on arrhythmic burden and HF symptoms, as well as an improvement in mortality. This review focuses on the role of CA for AF patients with HFrEF.

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: Karl-Heinz Kuck is associated with Stereotaxis, Inc., and Biotronik GmbH, is a scientific advisor for Endosense, and is a shareholder in Endosense. The investigator and senior author was not yet holding shares in the company until 3 months after completion of the study's primary end point. Therefore, the ethics committee was not informed of such participation; Vivek Reddy is associated with Ev3, Voyage Medical, and CardioFocus and is a scientific advisor for Endosense; Andrea Natale is a scientific advisor for Endosense and is associated with Hansen Medical, St Jude Medical, and Biosense Webster; Petr Neuzil is associated with Ev3 and Cryo Cath Technologies and is a consultant with Endosense; Nadir Saoudi is a scientific advisor for Edosense; Joseph Kautzner is associated with Medtronic, Biosense Webster, Inc., Boston Scientific Corp./EP Technologies, Hansen Medical, St Jude Medical, Biotronik GmbH, and the Sorin Group; Claudia Herrera is a consultant with Endosense; Gerhard Hindricks is associated with St Jude Medical; Pierre Jaïs is associated with Biosense Webster, Inc., St Jude Medical, and Voyage Medical; Hiroshi Nakagawa is associated with AtriCure, Biosense Webster, Inc., ProRythm, Inc., St Jude Medical Atrial Fibrillation, Endosense, and Biotronik GmbH; Hendrik Lambert is employed with Endosense; and Dipen C. Shah is a scientific advisor for Endosense and a shareholder in Endosense.

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ClinicalAblationA novel radiofrequency ablation catheter using contact force sensing: Toccata study

Objectives

Background

Methods

Results

Conclusions

Introduction

Section snippets

Patients

Right-sided SVT group

Discussion

Conclusions

Acknowledgments

Heart Rhythm

Europace

Treatment of supraventricular tachycardia due to atrioventricular nodal reentry, by radiofrequency catheter ablation of slow-pathway conduction

N Engl J Med

Efficacy and safety of an irrigated-tip catheter for the ablation of accessory pathways resistant to conventional radiofrequency ablation

Circulation

Novel CF sensor incorporated in irrigated radiofrequency ablation catheter predicts lesion size and incidence of steam pop and thrombus

Circ Arrhythmia Electrophysiol

Importance of catheter contact force during irrigated radiofrequency ablation: evaluation in a porcine ex vivo model using a force-sensing catheter

J Cardiovasc Electrophysiol

Role of contact force in esophageal injury during left atrial radiofrequency ablation

Heart Rhythm Society

Clinical
Ablation
A novel radiofrequency ablation catheter using contact force sensing: Toccata study