Remotely controlled steerable sheath improves result and procedural parameters of atrial fibrillation ablation with magnetic navigation

Ablation apprentices and their first experience of pulmonary vein isolation procedure on paroxysmal atrial fibrillation with different sheaths

OBJECTIVES

This study aimed at exploring how using different kinds of sheaths will affect the very first ablation procedure of apprentices.

METHODS

15 patients with paroxysmal atrial fibrillation were randomized to used fixed-curve, conventional steerable or visualized steerable sheath, and received complete isolation of pulmonary veins. All ablations were the very first procedure performed by 15 ablation apprentices. The use of fluoroscopy and catheter stability during the PVI were analyzed.

RESULTS

Procedure duration was much longer in the fixed-curve group (116.8 ± 27 vs. 62.2 ± 17 vs. 60.4 ± 17, p < 0.001). X-ray exposure was lowest with visualized sheath (17.6 ± 5 vs. 18.6 ± 6 vs. 5.2 ± 6, p < 0.001). CF SD differed significantly, especially at the anterior aspect of LSPV (7.90 ± 2.90 vs. 5.04 ± 2.18 vs. 4.52 ± 2.40, p < 0.001) and posterior aspect of RSPV (6.84 ± 2.79 vs. 3.42 ± 2.04 vs. 3.50 ± 2.30, p < 0.001) in the fixed-curve group. Impedance drop was significantly smaller in the fixed-curve group at the anterior aspect of LSPV (8.74 ± 3.02 vs. 11.49 ± 5.48 vs. 12.57 ± 5.96, p = 0.005).

CONCLUSION

Even for the very first ablation procedure of an ablation apprentice, the use of steerable sheaths will significantly reduce the procedure duration and improve the catheter stability, but only visualized steerable sheath can reduce fluoroscopic time.

Steerable versus nonsteerable sheath technology in atrial fibrillation ablation: A systematic review and meta-analysis

Introduction

Catheter placement and stability are well-known challenges in atrial fibrillation (AF) ablation. As a result, steerable sheaths (SS) were developed to improve catheter stabilization and maintain proper catheter-tissue contact. The purpose of this systematic review and meta-analysis is to see if employing a SS influences procedure outcome.

Method

We performed a comprehensive literature search for studies that evaluated the efficacy and safety of SS compared to nonsteerable sheaths (NSS) in AF ablation. The primary outcome was the rate of atrial arrhythmia (AA) freedom by the time of the last follow-up. The secondary outcomes were the procedure-related complications and procedural characteristics. Risk ratio (RR) or the mean difference (MD) and corresponding 95% confidence intervals (CIs) were calculated using the random-effects model.

Results

A total of 10 studies, including 967 AF patients (mean age: 59.2 ± 11.1 years, 516 patients managed with SS vs. 454 with NSS), were included. SS group showed a higher rate of freedom of AA compared to NSS (RR: 1.19; 95% CI 1.09-1.29; p < .001). Both techniques had similar rate for procedural-related complication (RR: 1.09, 95% CI 0.50-2.39; p = .83). The SS strategy had a shorter procedure time (MD -10.6 [min], 95% CI -20.97, -0.20; p = .05) but comparable fluoroscopic and radiofrequency application times to the NSS group.

Conclusions

The SS for AF catheter ablation not only reduced the total procedure time but also significantly increased the rate of successful ablation while maintaining a similar safety profile when compared to the traditional NSS.

Comprehensive strategies to minimize radiation exposure during Interventional electrophysiology procedures: state-of-the-art review

INTRODUCTION

Cardiac electrophysiology (EP) procedures are frequently performed in patients with cardiac arrhythmias, chronic heart failure, and sudden cardiac death. Most EP procedures involve fluoroscopy, which results in radiation exposure to physicians, patients, and EP lab staff. Accumulated radiation exposure is a known health detriment to patients and physicians.

AREA COVERED

This review will summarize radiation exposure, dose metrics, complications of radiation exposure, factors affecting radiation exposure, minimizing radiation exposure, zero or near-zero fluoroscopy strategies, and up-to-date research in the area of reducing radiation exposure and best practices.

EXPERT COMMENTARY

Comprehensive strategies should be implemented in EP laboratories to minimize radiation exposure with standard fluoroscopy. There are routine techniques that can mitigate significant amounts of radiation exposure using standard equipment within the EP lab. The operators need to emphasize that EP practices routinely incorporate non-ionizing radiation sources for cardiac imaging (e.g. magnetic resonance imaging, advanced electroanatomical mapping systems, intracardiac ultrasonography) in addition to other novel technologies to mitigate radiation exposure to patients and physicians.

Quantitative analysis of ablation technique predicts arrhythmia recurrence following atrial fibrillation ablation

BACKGROUND

Optimal ablation technique, including catheter-tissue contact during atrial fibrillation (AF) radiofrequency (RF) ablation, is associated with improved procedural outcomes. We used a custom developed software to analyze high-frequency catheter position data to study the interaction between catheter excursion during lesion placement, lesion-set sequentiality, and arrhythmia recurrence.

METHODS

A total of 100 consecutive patients undergoing first-time RF ablation for paroxysmal AF were analyzed. Spatial positioning of the ablation catheter sampled at 60 Hz during RF application was extracted from the CARTO3 system (Biosense Webster Inc, USA) and analyzed using custom-developed MATLAB software to determine precise catheter spatial 3D excursion during RF ablation. The primary end point was freedom from atrial arrhythmia lasting longer than 30 seconds after a single ablation procedure.

RESULTS

At 1 year, 86% of patients were free from recurrent arrhythmia. There was no significant difference in clinical, echocardiographic, or ablation characteristics between patients with and without recurrent arrhythmia. Analyzing 15,356,998 position data points revealed that lesion-set sequentiality and mean lesion catheter excursion were predictors of arrhythmia recurrence. Analyzing arrhythmia recurrence by mean single-lesion catheter excursion (excursion >2.81 mm) and by sequentiality (using 46% of lesions with interlesion distance >6 mm as cutoff) revealed significantly increased arrhythmia recurrence in the higher excursion group (23% vs 6%, P = .03) and in the less sequential group (24% vs 4%, P = .02).

CONCLUSIONS

Ablation lesion sequentiality measured by catheter interlesion distance and catheter stability measured by catheter excursion during lesion placement are potentially modifiable factors affecting arrhythmia recurrence after RF ablation for AF.

How is Contact Force implemented in routine clinical practice? Results from a French National and Monaco Survey

BACKGROUND

Combination of elementary parameters (force, time, power, impedance drop) has been proposed to optimize radiofrequency (RF) delivery. They have been partially validated in clinical studies.

AIMS

The aim of this study was to assess contact-force (CF) implementation into clinical practice.

METHODS

A 36-question electronic form was sent to 105 electrophysiologists (EP) including some general questions concerning the practice of catheter atrial fibrillation ablation and items concerning the parameters used for CF-guided ablation.

RESULTS

Answers from 98 EP were collected (93% response rate). The CF-catheters used were Smart Touch, Biosense (52%), Tacticath, Saint-Jude Medical (12%), or both (27%) and no CF (9%). The power applied on the left atrial (LA) anterior (LAAW) and posterior (LAPW) wall was, respectively, 26-34 W (for 73% of the EP) and below 25 W (88% of the EP). Forty percent of the Visitag® users mostly used the nominal parameters. Seventy-five percent of the users did not use automatic display of the impedance drop. For the Tacticath users, 57% used a target value of 400 gs on the LAAW and 300 to 400 gs on the LAPW. Lesion Size Index was exceptionally used.

CONCLUSIONS

The parameters used for CF-guided ablation are widely variable among the different operators. Further prospective studies are needed to validate the targets for automatic annotation of the RF applications.

Comparisons of efficacy, safety, and recurrence risk factors of paroxysmal and persistent atrial fibrillation catheter ablation using robotic magnetic navigation system

Background

No data exist on comparisons of efficacy, safety, and recurrence risk factors of paroxysmal and persistent atrial fibrillation (AF) ablation using robotic magnetic navigation system (MNS), respectively.

Methods

About 151 AF patients were prospectively enrolled and divided into paroxysmal AF group (n = 102) and persistent AF group (n = 49). Circumferential pulmonary vein antrum isolation (CPVI) was performed in all patients. Linear ablation at the left atrial roof and mitral isthmus was performed in patients with persistent AF in addition to CPVI. The procedural time, X‐ray exposure time, acute and long‐term success rates of CPVI, and procedure‐related complications were analyzed. The AF recurrence rates in the two groups were compared during 1 year, and Cox regression was used to analyze the recurrence risk factors.

Results

The acute success rates of CPVI in the two groups were 98.04% and 97.96%, respectively. There were no significant differences in the procedural time, X‐ray exposure time, and ablation time between the two groups (P > 0.05). No serious complications appeared in either group. The AF ablation success rates were 70.6% and 57.1% for the paroxysmal and persistent groups respectively at 12‐month follow‐up (P = 0.102). AF duration and coronary heart disease prior to ablation were associated with the higher AF recurrence in patients with persistent AF.

Conclusion

Ablation using MNS is effective and safe both in patients with paroxysmal and persistent AF. AF duration and coronary heart disease prior to ablation are two independent risk factors of AF recurrence in patients with persistent AF postoperatively.

Minimizing Radiation in the Modern Electrophysiology Laboratory

Historically, the electrophysiology laboratory has relied heavily on the use of ionizing radiation in the form of fluoroscopy for a broad range of interventions and diagnostics. As the harmful effects of radiation have become increasingly recognized and procedural technologies have advanced, electrophysiologists have adopted new workflows. The purpose of this article is to review the available literature and experience in minimizing radiation in the modern electrophysiology laboratory. This review first covers general approaches to reducing fluoroscopy radiation in the electrophysiology suite, with concepts that apply across all procedure types. These include the reduction of infrared emission through fastidious fluoroscopy settings, new and proven solutions for radiation shielding, and methods of creating distance between the radiation source and the operator to reduce exposure. Following this discussion, we review specific task-based techniques for reducing radiation during special electrophysiologic procedures and workflows such as vascular access, coronary sinus lead placement, catheter manipulation, and periprocedural planning studies.

Steering Sheath for 2-Nostril Transnasal Office Laryngoscopy

OBJECTIVE

The aim was to study the feasibility of performing office-based laryngeal procedures employing a flexible hollow steerable sheath placed contralateral to the nostril through which a standard flexible video endoscope is placed.

METHODS

The study design included simulation of transnasal endoscopic laryngeal procedures evaluating the use of a flexible steering sheath in laboratory and clinic settings. Transnasal laryngeal procedures were performed in an otolaryngology office setting employing an airway-management-trainer mannequin and then repeated in a human cadaver lab with standard transnasal flexible video laryngoscopy. Video documentation assessed use of a lever-manipulated deflecting ureteral access sheath with an inner diameter of 2.97 mm, an outer diameter of 4.95 mm, and a length of 45 cm. Simulated transnasal laryngoscopy procedures deployed devices through the deflecting sheath to mimic vocal fold needle injection, biopsy with forceps, balloon dilation, and laser treatment to identify strengths and shortcomings to the technology and technique.

RESULTS

Simulation was successful in appropriately directing instrumentation for all procedures tested. Shortcomings included limitations in steering capacity, greater length to the sheath than desirable for laryngeal procedures, and the need for additional assistants to perform procedures.

CONCLUSION

Steering sheath technology is applicable to enhance in-office transnasal laryngoscopy procedures.

Radiofrequency catheter ablation of atrial fibrillation: Electrical modification suggesting transmurality is faster achieved with remote magnetic catheter in comparison with contact force use

BACKGROUND

Remote magnetic navigation (RMN) and contact force (CF) sensing catheters are available technologies for radiofrequency (RF) catheter ablation of atrial fibrillation (AF). Our purpose was to compare time to electrogram (EGM) modification suggesting transmural lesions between RMN and CF-guided AF ablation.

METHODS AND RESULTS

A total of 1,008 RF applications were analyzed in 21 patients undergoing RMN (n = 11) or CF-guided ablation (n = 10) for paroxysmal AF. All procedures were performed in sinus rhythm during general anesthesia. Time to EGM modification was measured until transmurality criteria were fulfilled: (1) complete disappearance of R if initial QR morphology; (2) diminution > 75% of R if initial QRS morphology; (3) complete disappearance of R' of initial RSR' morphology. Impedance drop as well as force time integral (FTI) were also assessed for each application. Mean CF at the beginning of each RF application in the CF group was 11 ± 2 g and mean FTI per application was 488 ± 163 gs. Time to EGM modification was significantly shorter in the RMN group (4.52 ± 0.1 seconds vs. 5.6 ± 0.09 seconds; P < 0.00001). There was no significant difference between other procedural parameters.

CONCLUSION

Remote magnetic AF ablation is associated with faster EGM modification suggesting transmurality than optimized CF and FTI-guided catheter ablation.

Selection of Critical Isthmus in Scar-Related Atrial Tachycardia Using a New Automated Ultrahigh Resolution Mapping System

Background—

Accurate activation mapping of reentrant scar-related atrial tachycardias (AT) allows efficient radiofrequency ablation by targeting the critical isthmus (CI). We aimed to assess the electrophysiological properties of CI channels during mapping with the IntellaMap Orion basket and the Rhythmia system.

Methods and Results—

We prospectively studied 33 AT (post– atrial fibrillation ablation or surgical mitral valve repair). The noise of bipolar electrogram (EGM) was systematically measured at 10 prespecified sites, as well as on a standard catheter and on the surface ECG. Bipolar EGM of CI regions were analyzed for amplitude, duration, and conduction velocity. The isthmus region to be targeted was chosen based solely on propagation. For each AT, 25 684±14 276 EGMs were automatically annotated. Noise of the Orion EGM was 0.011±0.004 mV, lower than that of a standard catheter (0.016±0.019) and surface ECG (0.02±0.01; P <0.05). For reentrant AT, within the CI, bipolar EGM amplitude (0.08±0.11 mV) and conduction velocity (0.27±0.19 m/s) were lower than those orthodromically before (0.62±0.93 mV; 1±0.49 m/s) and after (0.80±1.59 mV; 1±0.73 m/s) the isthmus ( P <0.001 for all). In 97% of AT, ablation at the CI resulted in AT termination. No complications occurred.

Conclusions—

This new automated ultrahigh resolution mapping system produces low noise and allows accurate diagnosis of AT circuits. CI on reentrant scar-related AT showed much lower EGM amplitude with a significantly slower conduction velocity than the surrounding parts of the circuit. Ablation of the areas of slow conduction resulted in a high acute success.

Remote Magnetic Navigation: A Focus on Catheter Ablation of Ventricular Arrhythmias

VT ablation is based on percutaneous catheter insertion under fluoroscopic guidance to selectively destroy (i.e., ablate) myocardial tissue regions responsible for the initiation or propagation of ventricular arrhythmias. Although the last decade has witnessed a rapid evolution of ablation equipment and techniques, the control over catheter movement during manual ablation has remained largely unchanged. Moreover, the procedures are long, and require ergonomically unfavorable positions, which can lead to operator fatigue. In an attempt to overcome these constraints, several technical advancements, including remote magnetic navigation (RMN), have been developed. RMN utilizes a magnetic field to remotely manipulate specially designed soft-tip ablation catheters anywhere in the x, y, or z plane inside the patient's chest. RMN also facilitates titration of the contact force between the catheter and the myocardial tissue, which may reduce the risk of complications while ensuring adequate lesion formation. There are several non-randomized studies showing that RMN has similar efficacy to manual ablation, while complication rates and total radiation exposure appears to be lower. Although these data are promising, larger randomized studies are needed to prove that RMN is superior to manual ablation of VT.

Atrial Fibrillation Ablation Using Magnetic Navigation Comparison With Conventional Approach During Long-Term Follow-Up

Atrial fibrillation (AF) ablation targeting the circumferential isolation of pulmonary veins (PVI) is an established therapeutic alternative in symptomatic AF patients resistant to anti-arrhythmic medications. The procedure is technically challenging and multiple difficulties must be overcome in order to achieve a successful outcome. The magnetic navigation system (MNS) is a remote catheter control technology which has advantages such as a traumatic catheter design improving the procedural safety, a reduced amount of radiation exposure to both the patient and physician, unrestricted and reproducible catheter maneuverability that allows the access to difficult anatomical situations, and an improved catheter stability leading to better energy delivery. Due to these advantages, MNS is increasingly being used for AF ablation and both acute and chronic success rates are comparable with the conventional technique. The new developments in navigation systems, catheters and new three-dimensional mapping systems are very promising to obviate these concerns. However, MNS is related to longer radiofrequency (RF) application duration and procedure time.