Impact of Remote Magnetic Catheter Navigation on Ablation Fluoroscopy and Procedure Time

Muscle usage and workload assessment of cardiac ablation procedure with the use of a novel catheter torque tool in a pediatric simulator

BACKGROUND

Cardiac ablation catheters are small in diameter and pose ergonomic challenges that can affect catheter stability. Significant finger dexterity and strength are necessary to maneuver them safely. We evaluated a novel torque tool to reduce muscle activation when manipulating catheters and improve perceived workload of ablation tasks. The objective was to evaluate measurable success, user perception of workload, and muscle usage when completing a simulated ablation task with and without the use of a catheter torque tool.

METHODS

Cardiology attendings and fellows were fitted with surface electromyographic (EMG) sensors on 6 key muscle groups in the left hand and forearm. A standard ablation catheter was inserted into a pediatric cardiac ablation simulator and subjects navigated the catheter tip to 6 specific electrophysiologic targets, including a 1-min simulated radiofrequency ablation lesion. Time to complete the task, number of attempts required to complete the lesion, and EMG activity normalized to percentage of maximum voluntary contraction were collected throughout the task. The task was completed 4 times, twice with and twice without the torque tool, in semi-randomized order. A NASA Task Load Index survey was completed by the participant at the conclusion of each task.

RESULTS

Time to complete the task and number of attempts to create a lesion were not altered by the tool. Subjectively, participants reported a significant decrease in physical demand, effort, and frustration, and a significant increase in performance. Muscle activation was decreased in 4 of 6 muscle groups.

CONCLUSION

The catheter torque tool may improve the perceived workload of cardiac ablation procedures and reduce muscle fatigue caused by manipulating catheters. This may result in improved catheter stability and increased procedural safety.

Guide-Wired Helical Microrobot for Percutaneous Revascularization in Chronic Total Occlusion in-Vivo Validation

OBJECTIVE

For the revascularization in small vessels such as coronary arteries, we present a guide-wired helical microrobot mimicking the corkscrew motion for mechanical atherectomy that enables autonomous therapeutics and minimizing the radiation exposure to clinicians.

METHODS

The microrobot is fabricated with a spherical joint and a guidewire. A previously developed external electromagnetic manipulation system capable of high power and frequency is incorporated and an autonomous guidance motion control including driving and steering is implemented in the prototype. We tested the validity of our approach in animal experiments under clinical settings. For the in vivo test, artificial thrombus was fabricated and placed in a small vessel and atherectomy procedures were conducted.

RESULTS

The devised approach enables us to navigate the helical robot to the target area and successfully unclog the thrombosis in rat models in vivo.

CONCLUSION

This technology overcomes several limitations associated with a small vessel environment and promises to advance medical microrobotics for real clinical applications while achieving intact operation and minimizing radiation exposures to clinicians.

SIGNIFICANCE

Advanced microrobot based on multi-discipline technology could be validated in vivo for the first time and that may foster the microrobot application at clinical sites.

Radiofrequency atrial fibrillation ablation with irrigated tip catheter using remote magnetic navigation compared with conventional manual method

BACKGROUND

Studies comparing manual catheter navigation (MCN) to remote magnetic navigation (RMN) for atrial fibrillation (AF) ablation showed variable results.

OBJECTIVE

The aim of this meta-analysis is to compare the safety and clinical outcomes of AF radiofrequency (RF) ablation using MCN versus RMN with irrigated tip catheters.

METHODS

Medline and the Cochrane Central Register of Controlled Trials (CENTRAL) were queried from inception through January 2019. Studies comparing safety and clinical outcomes of AF ablation with RF using MCN versus RMN with irrigated tip catheters were included. Random effects meta-analysis was used to pool outcomes across studies. Study endpoints included freedom of AF at the end of the study, procedure total time, fluoroscopy time, and complications.

RESULTS

A total of 14 studies (3 controlled non-randomized trials, 1 prospective observational, and 10 retrospective observational studies) involving 3375 patients (1871 in MCN and 1504 in RMN) were included in this meta-analysis. There was no significant difference between the two groups in terms of freedom of AF (OR 1.08, 95% CI 0.82-1.42, p = 0.52). The MCN group was associated with shorter procedure time (mean difference in minutes - 50.39, 95% CI - 67.99 to - 32.79, p < 0.01), longer fluoroscopy time (mean difference in minutes 18.01, 95% CI 10.73-25.29, p < 0.01), and higher complication rate (OR 2.18, 95% CI 1.24-3.82, p < 0.01).

CONCLUSIONS

AF ablation utilizing MCN was associated with similar efficacy to RMN but with higher complication rates. Although the procedure time was shorter with MCN, the fluoroscopy time was more prolonged. Randomized clinical studies are needed to further verify these results.

Introducing a novel catheter-tissue contact feedback feature in robotic navigated catheter ablation: Utility, feasibility, and safety

Background

The quality of catheter–tissue contact is one of the most important determinants of catheter ablation (CA) success. The absence of catheter–tissue contact feedback has been regarded a major limitation of remote magnetic navigation (RMN)–guided CA. The e-Contact module (ECM) is a novel feature designed for RMN that measures the quality of catheter–tissue contact.

Objective

The purpose of this study was to describe the first clinical experience with this feature and to test its effect on procedural parameters and interference with other ablation equipment during CA procedures as well as its safety.

Methods

This was a prospective, single-center, 2-phase study investigating ECM use during complex RMN procedures in 30 patients. Impact of ECM on procedural parameters was evaluated in the feasibility phase (FP), and its interference with other equipment was tested in the interference phase (IP) using pacing maneuvers at 3 randomly selected right atrial sites. Intracardiac electrograms were evaluated for disturbances by 2 independent electrophysiologists.

Results

For FP, mean procedural time was 162 ± 66 minutes, fluoroscopy time 21 ± 9 minutes, and ablation time 34 ± 21 minutes. For IP, no significant differences in pacing capture or thresholds were found (ECM– vs ECM+: site 1: 2.05 vs 2.21 mA; P = .320; site 2: 2.15 vs 2.12 mA; P = .873; site 3: 2.51 vs 2.50 mA; P = .976). Electrogram disturbances did not significantly differ between ECM– and ECM+. No adverse events were reported.

Conclusion

The ECM is a novel catheter–tissue contact technology designed for RMN-guided CA. Our study suggests that this feature is feasible and does not interfere with other electrophysiology equipment while maintaining an excellent safety profile.

Steerable catheters for minimally invasive surgery: a review and future directions

The steerable catheter refers to the catheter that is manipulated by a mechanism which may be driven by operators or by actuators. The steerable catheter for minimally invasive surgery has rapidly become a rich and diverse area of research. Many important achievements in design, application and analysis of the steerable catheter have been made in the past decade. This paper aims to provide an overview of the state of arts of steerable catheters. Steerable catheters are classified into four main groups based on the actuation principle: (1) tendon driven catheters, (2) magnetic navigation catheters, (3) soft material driven catheters (shape memory effect catheters, steerable needles, concentric tubes, conducting polymer driven catheters and hydraulic pressure driven catheters), and (4) hybrid actuation catheters. The advantages and limitations of each of them are commented and discussed in this paper. The future directions of research are summarized.

Remote magnetic navigation versus manual control navigation for atrial fibrillation ablation: A systematic review and meta-analysis

BACKGROUND

The aim of this review was to evaluate the efficacy and safety between remote magnetic navigation (RMN) and manual control navigation (MCN) for atrial fibrillation (AF) ablation.

METHODS

We searched the PubMed, EMBASE and Cochrane library databases using the key words AF, ablation and magnetic navigation.

RESULTS

Eighteen studies were identified in this analysis including 4046 patients comparing RMN and MCN in AF ablation, which were all non-randomized controlled studies. No significant difference of AF recurrence rate (40% vs. 38%, OR 1.00, 95% CI 0.82-1.22, p = 0. 97) and acute success rate in achieving pulmonary vein isolation (91% vs. 93%, OR 0.44, 95% CI 0.16-1.17, p = 0.10) was found between RMN and MCN. However, compared with MCN, RMN was associated with significantly lower complication rate (2% vs. 5%, OR 0.44, 95% CI 0.28-0.69, p = 0. 0003) and shorter fluoroscopy time (MD -9.71 min, 95% CI -15.80 to -3.63, p = 0.002). Procedure time (MD 47.05 min, 95% CI 27.5-66.58, p < 0.00001) and ablation time (MD 15.90 min, 95% CI 9.62-22.18, p < 0.00001) of RMN guided AF ablation were significantly longer than those of MCN.

CONCLUSION

The results of this study suggest that RMN is as effective as MCN in achieving pulmonary vein isolation and freedom from AF recurrence, and has superior safety with less complications and shorter fluoroscopy time.

Atrioventricular node reentrant tachycardia: Remote magnetic navigation ablation versus manual ablation - impact on operator fluoroscopy time

INTRODUCTION AND AIMS

Remote magnetic navigation systems have demonstrated benefits in the ablation of difficult substrates. Their role in the ablation of atrioventricular nodal reentrant tachycardia (AVNRT), however, has only been studied in small patient series. The aim of this study was to compare the results of AVNRT ablation using magnetic navigation, in a center where every procedure is performed with this system, with manual ablation.

METHODS

We selected 139 consecutive patients undergoing AVNRT ablation with magnetic navigation by a single operator between January 2009 and June 2016 and compared them to a group of 101 consecutive patients undergoing manual ablation in the same period by the same operator in another hospital. The methodology was the same in both groups. Success rates, complications, procedure time, radiofrequency time, total and operator fluoroscopy time, and recurrence rates were compared.

RESULTS

There were no differences in success and complication rates. Procedure and total fluoroscopy times were not significantly different, but operator fluoroscopy time was significantly shorter with the magnetic navigation system (2.4±1.5 min vs. 7.2±4 min; p<0.001). The recurrence rate was higher in the manual group, although without statistical significance.

CONCLUSIONS

The ablation of AVNRT with magnetic navigation is feasible using the same methodology as for manual ablation. Success and complication rates were similar. Operator fluoroscopy time was significantly less with the magnetic navigation system.

X-Ray Exposure in Cardiac Electrophysiology: A Retrospective Analysis in 8150 Patients Over 7 Years of Activity in a Modern, Large-Volume Laboratory

Background

Only a few studies have systematically evaluated fluoroscopy data of electrophysiological and device implantation procedures. Aims of this study were to quantify ionizing radiation exposure for electrophysiological/device implantation procedures in a large series of patients and to analyze the x‐ray exposure trend over years and radiation exposure in patients undergoing atrial fibrillation ablation considering different technical aspects.

Methods and Results

We performed a retrospective analysis of all electrophysiological/device implantation procedures performed during the past 7 years in a modern, large‐volume laboratory. We reported complete fluoroscopy data on 8150 electrophysiological/device implantation procedures (6095 electrophysiological and 2055 device implantation procedures); for each type of procedure, effective dose and lifetime attributable risk of cancer incidence and mortality were calculated. Over the 7‐year period, we observed a significant trend reduction in fluoroscopy time, dose area product, and effective dose for all electrophysiological procedures (P<0.001) and a not statistically significant trend reduction for device implantation procedures. Analyzing 2416 atrial fibrillation ablations, we observed a significant variability of fluoroscopy time, dose area product and effective dose among 7 different experienced operators (P<0.0001) and a significant reduction of fluoroscopy use over time (P<0.0001) for all of them. Considering atrial fibrillation ablation techniques, fluoroscopy time was not different (P = 0.74) for radiofrequency catheter ablation in comparison with cryoablation, though cryoablation was still associated with higher dose area product and effective dose values (P<0.001).

Conclusions

Electrophysiological procedures involve a nonnegligible x‐ray use, leading to an increased risk of malignancy. Awareness of radiation‐related risk, together with technological advances, can successfully optimize fluoroscopy use.

Long-term clinical outcomes of magnetically navigated rotor ablation as an adjunct to conventional pulmonary vein isolation

Aims

The objective of this study is to evaluate the outcomes of magnetically guided ablation of atrial fibrillation (AF) rotors in conjunction with magnetically guided pulmonary vein isolation (PVI) in a large consecutive series of patients.

Methods and results

A total of 110 consecutive patients with drug-refractory AF underwent rotor ablation followed by conventional PVI and ablation of other spontaneous arrhythmias, all of which were performed with remote magnetic navigation (RMN). The patients were followed to assess the recurrence of atrial arrhythmia. Patients had a mean age of 62.5 ± 9.9 years, 64.5% had persistent AF, and 36.4% had a prior failed PVI. All patients had mapped rotors (3.9 ± 1.5 per patient), with right atrial (RA) rotors in 77.3% (85/110) of patients. After a mean follow-up of 17.6 ± 9.5 months, 90.9% (100/110) were in stable sinus rhythm including patients on previously ineffective antiarrhythmic drugs (AADs). 69.1% (76/110) were in stable sinus rhythm without any AADs. Outcome did not differ between patients with persistent or paroxysmal AF (69.2% vs. 69.0%; P = 0.75), failed prior ablation or those undergoing an initial ablation (77.5% vs. 64.3%; P = 0.193), or patients with and without intra-procedural AF termination (67.3% vs. 70.5%; P = 0.723).

Conclusion

Ablation of rotors in combination with PVI using RMN was associated with a high success rate in this large cohort of consecutive patients. Significant proportion of patients exhibited RA rotors, which was associated with persistent AF, obstructive sleep apnoea, and obesity.

Remote magnetic catheter navigation versus conventional ablation in atrial fibrillation ablation: Fluoroscopy reduction

Background

Percutaneous transcatheter radiofrequency ablation of atrial fibrillation with remote controlled magnetic navigation (RMN) has been shown to reduce radiation exposure to patients and physicians compared with conventional manual (MAN) ablation techniques.

Methods

Catheter ablation for atrial fibrillation was performed utilizing RMN in 214 consecutive patients and MAN ablation techniques in 229 patients. We compared the fluoroscopy and procedural times between RMN and MAN catheter ablation of atrial fibrillation. Secondary objectives included comparing acute procedural success and short-term complication rates between both ablation strategies.

Results

Fluoroscopy time was significantly shorter in the RMN group than the MAN group (53.5±30.1 vs 68.1±27.6 min, respectively; p<0.01); however, the total procedural time was longer in the RMN group (280.2±74.4 min vs 213.1±64.75, respectively; p>0.001). Further subgroup analysis of the most recent 50 ablations each from the RMN and MAN groups, to attenuate the RMN learning curve effect, showed an even greater difference in fluoroscopy time (RMN vs MAN: 53.5±30.1 vs 68.1±27.6 min), though a consistently longer procedure time with RMN (249.5±65.5 vs 186.3±65.6 min, respectively). The acute procedural success rate was comparable between the groups (98.6% vs 95.6%, respectively; p=0.07). The rates of acute complications were similar in both groups (2.3% vs 4.8%, respectively; p=0.16).

Conclusions

In radiofrequency ablation of atrial fibrillation, RMN appears to significantly reduce fluoroscopy time compared with conventional MAN ablation, though at a cost of increased total procedural time, with comparable acute success rates and safety profile. A reduction in procedure and fluoroscopy times is possible with gaining experience.

Robotic magnetic navigation for ablation of human arrhythmias

Radiofrequency treatment represents the first choice of treatment for arrhythmias, in particular complex arrhythmias and especially atrial fibrillation, due to the greater benefit/risk ratio compared to antiarrhythmic drugs. However, complex arrhythmias such as atrial fibrillation require long procedures with additional risks such as X-ray exposure or serious complications such as tamponade. Given this context, the treatment of arrhythmias using robotic magnetic navigation entails a technique well suited to complex arrhythmias on account of its efficacy, reliability, significant reduction in X-ray exposure for both patient and operator, as well as a very low risk of perforation. As ongoing developments will likely improve results and procedure times, this technology will become one of the most modern technologies for treating arrhythmias. Based on the literature, this review summarizes the advantages and limitations of robotic magnetic navigation for ablation of human arrhythmias.

Remote magnetic navigation vs. manual navigation for ablation of ventricular tachycardia: a meta-analysis

BACKGROUND

The purpose of this study was to prospectively evaluate the efficacy and safety of remote magnetic navigation (RMN) in comparison with manual catheter navigation (MCN) in performing ventricular tachycardia ablation.

METHODS

An electronic search was performed using PubMed (1948-2013) and EMBASE (1974-2013) studies comparing RMN with MCN which were published prior to 31 December 2013. Outcomes of interest were as follows: acute success, recurrence rate, complications, total procedure and fluoroscopic times. Standard mean difference (SMD) and its 95 % confidence interval (CI) were used for continuous outcomes; odds ratios (OR) were reported for dichotomous variables.

RESULTS

Four non-randomised studies, including a total of 328 patients, were identified. RMN was deployed in 191 patients. Acute success and long-term freedom from arrhythmias were not significantly different between the RMN and control groups (OR 1.845, 95 % CI 0.731-4.659, p = 0.195 and OR 0.676, 95 % CI 0.383-1.194, p = 0.177, respectively). RMN was associated with less peri-procedural complications (OR 0.279, 95 % CI 0.092-0.843, p = 0.024). Shorter procedural and fluoroscopy times were achieved (95 % CI -0.487 to -0.035, p = 0.024 and 95 % CI -1.467 to -0.984, p<0.001, respectively).

CONCLUSION

The acute and long-term success rates for VT ablation are equal between RMN and MCN, whereas the RMN-guided procedure can be performed with a lower complication rate and less procedural and fluoroscopic times. More prospective randomised trials will be needed to better evaluate the superior role of RMN for catheter ablation of ventricular tachycardia.

Atrial fibrillation ablation using remote magnetic navigation and the risk of atrial-esophageal fistula: international multicenter experience

PURPOSE

Remote magnetic navigation (RMN) has been used in various electrophysiological procedures, including atrial fibrillation (AF) ablation. Atrial-esophageal fistula (AEF) is one of most disastrous complications of AF ablation. We aimed to evaluate the incidence of AEF during AF ablation using RMN in comparison to manual ablation.

METHODS

We conducted the first international survey among RMN operators for assessment of the prevalence of AEF and procedural parameters affecting the risk. Data from parallel survey of AEF among Canadian interventional electrophysiologists (CIE) using only manual catheters served as control.

RESULTS

Fifteen RMN operators (who performed 3637 procedures) and 25 manual CIE operators (7016 procedures) responded to the survey. RMN operators were more experienced than CIE operators (16.3 ± 8.3 vs. 9.2 ± 5.4 practice years in electrophysiology, p = 0.007). The maximal energy output in the posterior wall was higher in the operator using RMN (33 ± 5 vs. 28.6 ± 4.9 W; p = 0.02). Other parameters including use of preprocedural images, irrigated catheter, pump flow rate, esophageal temperature monitoring, intracardiac echocardiography (ICE), and general anesthesia were similar. CIE operators administered proton-pump inhibitors postoperatively significantly more than RMN operators (76 vs. 35%, p = 0.01). AEF was reported in 5 of the 7016 patients in the control group (0.07%) but in none of the RMN group (p = 0.11).

CONCLUSIONS

AEF is a rare complication and its evaluation necessitates large-scale studies. Although no AEF case with RMN was reported in this large study or previously on the literature, the rarity of this complication prevents firm conclusion about the risk.

A prospective study on safety of catheter ablation procedures: contact force guided ablation could reduce the risk of cardiac perforation

BACKGROUND

Contact force (CF) sensing catheters provide advantages with regard to safety and efficacy. This study aimed to evaluate if CF catheters reduce cardiac perforations and other major complications and offer equal safety compared to the magnetic navigation system (MNS).

METHODS

Data from 1.517 ablation procedures from our prospective registry was analyzed. Ablations were performed using either CF guided catheters (CF group, n=248), non-CF catheters (NCF group, n=813), or MNS (n=456). Four subgroups were analyzed: atrial fibrillation (AF, n=557), supraventricular tachycardia (SVT, n=715), ventricular tachycardia (VT, n=190) and patients with congenital heart defects (CHD, n=55). The primary endpoint of this study was incidence of cardiac perforation. Secondary endpoints were major and minor complications within 30 days of the procedure.

RESULTS

Complications occurred in 11.3% (n=172) of the procedures. In 2.8% (n=43) a major complication occurred, 0.9% (n=13) had a perforation, 8.5% (n=129) had a minor complication and 2 patients died (0.1%). No cardiac perforation occurred in the CF group, which was significantly different from NCF procedures (0.0% vs. 1.6%; relative risk 0.76, 95% CI 0.74-0.79, P=0.031) and equal to MNS (0.0%). This was also observed in the AF subgroup (0.0% vs. 3.3%; RR 0.67, 95% CI 0.63-0.72, P=0.021), and the occurrence of major complications was lower for CF versus NCF procedures (2.1% vs. 7.8%, P=0.010).

CONCLUSIONS

CF-guided catheter ablation is superior to NCF with regard to procedural safety and avoidance of cardiac perforation. This difference is due to a reduction of cardiac perforation and major complications in the AF subgroup.

The Growing Culture Of A Minimally Fluoroscopic Approach In Electrophysiology Lab

Most of interventional procedures in cardiology are carried out under fluoroscopic imaging guidance. Besides other peri-interventional risks, radiation exposure should be considered for its stochastic (inducing malignancy) and deterministic effects on health (tissue reactions like erythema, hair loss and cataracts). In this article we analized the radiation risk from cardiovascular imaging to both patients and medical staff and discusses how customize the X-ray system and how to implement shielding measures in the cath lab. Finally, we reviewed the most recent developments and the latest findings in catheter navigation and 3D electronatomical mapping systems that may help to reduce patient and operator exposure.

Remote magnetic navigation for catheter ablation of atrioventricular nodal reentrant tachycardia: a systematic review and meta-analysis

Catheter ablation has become a well-established, first-line therapy for atrioventricular nodal reentrant tachycardia (AVNRT), the most common reentry supraventricular tachycardia in humans. Robotic systems are becoming increasingly common in both complex and simple ablation procedures with presumed potential improvements in procedural efficacy and safety. The authors of this article conducted a systematic review and meta-analysis on the effectiveness and safety of the magnetic navigation system (MNS) in comparison with conventional catheter navigation for AVNRT ablation. An electronic search was performed using Cochrane Central database, Medline, Embase and Web of Knowledge between 2002 and 2012. References were searched manually. Outcomes of interest were: acute and long-term success, complications, total procedure, ablation and fluoroscopic times. Continuous variables were reported as standardized difference in means (SDM); odds ratios (OR) were reported for dichotomous variables. Thirteen studies (seven of which were nonrandomized controlled, four were case series and two were randomized controlled studies) involving 679 adult patients were identified. Twelve studies were based on a single center and one study was multicentral. MNS was deployed in 339 patients. The follow-up period ranged between 75 and 180 days. Acute success and long-term freedom from arrhythmia were not significantly different between MNS and control groups (98 vs 98%, OR: 0.94 [95% CI: 0.21-4.1] and 97 vs 96%, OR: 1.18 [95% CI: 0.35-4.0], respectively). A shorter fluoroscopic time was achieved with MNS; however, this did not reach statistical significance (15 vs 19 min, SDM: -0.26 [95% CI: -0.64-0.12]). Longer total procedure but similar ablation times were noted with MNS (160 vs 148 min, SDM: 3.48 [95% CI: 0.75-6.21] and 4 vs 6 min, SDM: -0.83 [95% CI: -2.19-0.53], respectively). The overall complication rate was similar between both groups (2.7 vs 1.0%, OR: 1.28 [95% CI: 0.33-4.96]). Our data suggest that the usage of MNS results in similar rates of success and complications when compared with conventional manual catheter ablation for AVNRT. MNS had a trend for reduced fluoroscopic time. Longer total procedure time was observed with MNS while the actual ablation time remained similar. Prospective randomized trials will be needed to better evaluate the relative role of MNS for catheter ablation of AVNRT.

Does a patent foramen ovale matter when using a remote-controlled magnetic system for pulmonary vein isolation?

BACKGROUND

Pulmonary vein isolation (PVI) takes longer when using a patent foramen ovale (PFO) compared with a transseptal puncture in paroxysmal atrial fibrillation (AF) with manual catheter ablation. To our knowledge, no data exist concerning the impact of a PFO on AF ablation procedure variables when using a remote magnetic navigation (RMN) system.

AIM

To assess the impact of a PFO when using an RMN system in patients requiring AF ablation.

METHODS

Between December 2011 and December 2012, catheter ablation was performed remotely using the CARTO(®) 3 system in 167 consecutive patients who underwent PVI for symptomatic drug-refractory AF. The radiofrequency generator was set to a fixed power ≤ 35 W. The primary endpoint was wide-area circumferential PVI confirmed by spiral catheter recording during ablation for all patients and including additional lesion lines (left atrial roof) or complex fractionated atrial electrograms for persistent AF. Secondary endpoints included procedural data.

RESULTS

Mean age 58±10 years; 18% women; 107 (64%) patients with symptomatic paroxysmal AF; 60 (36%) with persistent AF; CHA2DS2-VASc score 1.2 ± 1. The PFO presence was evidenced in 49/167 (29.3%) patients during the procedure but in only 26/167 (16%) by transoesophageal echocardiography. Median procedure time 2.5 ± 1 hours; median total X-ray exposure time 14 ± 7 minutes; transseptal puncture and catheter positioning time 7.5 ± 5 minutes; left atrium electroanatomical reconstruction time 3 ± 2.3 minutes; catheter ablation time 3 ± 3 minutes. No procedure time or X-ray exposure differences were observed between patients with or without a PFO during magnetic navigation catheter ablation. X-ray exposure time was significantly reduced using a PFO compared with double transseptal puncture access.

CONCLUSIONS

A PFO does not affect magnetic navigation during AF ablation; procedure times and X-ray exposure were similar. Septal catheter probing is mandatory to limit X-ray exposure and prevent potential complications.

From passive tool holders to microsurgeons: safer, smaller, smarter surgical robots

Within only a few decades from its initial introduction, the field of surgical robotics has evolved into a dynamic and rapidly growing research area with increasing clinical uptake worldwide. Initially introduced for stereotaxic neurosurgery, surgical robots are now involved in an increasing number of procedures, demonstrating their practical clinical potential while propelling further advances in surgical innovations. Emerging platforms are also able to perform complex interventions through only a single-entry incision, and navigate through natural anatomical pathways in a tethered or wireless fashion. New devices facilitate superhuman dexterity and enable the performance of surgical steps that are otherwise impossible. They also allow seamless integration of microimaging techniques at the cellular level, significantly expanding the capabilities of surgeons. This paper provides an overview of the significant achievements in surgical robotics and identifies the current trends and future research directions of the field in making surgical robots safer, smaller, and smarter.

Outcomes of repeat catheter ablation using magnetic navigation or conventional ablation

AIMS

After initial catheter ablation, repeat procedures could be necessary. This study evaluates the efficacy of the magnetic navigation system (MNS) in repeat catheter ablation as compared with manual conventional techniques (MANs).

METHODS AND RESULTS

The results of 163 repeat ablation procedures were analysed. Ablations were performed either using MNS (n = 84) or conventional manual ablation (n = 79). Procedures were divided into four groups based on the technique used during the initial and repeat ablation procedure: MAN-MAN (n = 66), MAN-MNS (n = 31), MNS-MNS (n = 53), and MNS-MAN (n = 13). Three subgroups were analysed: supraventricular tachycardias (SVTs, n = 68), atrial fibrillation (AF, n = 67), and ventricular tachycardias (VT, n = 28). Recurrences were assessed during 19 ± 11 months follow-up. Overall, repeat procedures using MNS were successful in 89.0% as compared with 96.2% in the MAN group (P = ns). The overall recurrence rate was significantly lower using MNS (25.0 vs. 41.4%, P = 0.045). Acute success and recurrence rates for the MAN-MAN, MAN-MNS, MNS-MNS, and MNS-MAN groups were comparable. For the SVT subgroup a higher acute success rate was achieved using MAN (87.9 vs. 100.0%, P = 0.049). The use of MNS for SVT is associated with longer procedure times (205 ± 82 vs. 172 ± 69 min, P = 0.040). For AF procedure and fluoroscopy times were longer (257 ± 72 vs. 185 ± 64, P = 0.001; 59.5 ± 19.3 vs. 41.1 ± 18.3 min, P < 0.001). Less fluoroscopy was used for MNS-guided VT procedures (22.8 ± 14.7 vs. 41.2 ± 10.9, P = 0.011).

CONCLUSION

Our data suggest that overall MNS is comparable with MAN in acute success after repeat catheter ablation. However, MNS is related to fewer recurrences as compared with MAN.

Remote magnetic navigation in atrial fibrillation

Atrial fibrillation (AF) is of profound public health importance and is largely a disease of aging and is responsible for increased morbidity- and mortality-related healthcare expenditures. Catheter ablation to isolate the pulmonary veins has become the therapy of choice for treatment of drug-refractory AF. Procedures can be very challenging and multiple difficulties must be overcome in order to achieve a successful outcome. The magnetic navigation system (MNS) has advantages in catheter maneuverability, stability and reproducibility. Due to the catheter design safety and efficacy of AF, ablation has increased. New developments are being made to allow fully remote ablation procedures in combination with the MNS. However, new technologies are still necessary to improve MNS ablation for AF.

Forces on cardiac implantable electronic devices during remote magnetic navigation

BACKGROUND

Remote magnetic navigation systems are used for catheter navigation in cardiac electrophysiological ablation procedures. In this setting, ferromagnetic particles will be moved by changes in the magnetic field. It is unknown to what extent cardiac implantable electronic devices (CIED) are affected by the magnetic field when using magnetic navigation, and whether these forces may exceed the limit of 5 N that is set forth by German and European norms for implanted electrodes.

METHODS

A total of 121 rhythm devices were examined in a magnetic field of 0.1 T using the NIOBE II(®) Magnetic Navigation System (Stereotaxis, St. Louis, USA). Forces acting on the devices were measured with the force measurement tool Futek LRF 400 (Futek Advanced Sensor Technology Inc., Irvine, CA, USA). A standardized protocol of different movements of the magnetic field including all three dimensions was performed and maximal forces on the CIED were assessed.

RESULTS

Out of 121 devices, 78 different pacemakers (54 different model families from 11 manufacturers) and 43 different cardioverter-defibrillators (26 different model families from 6) were examined. The mean force that could be observed was 0.33 ± 0.13 N for pacemakers (range 0.16-1.12 N) and 1.05 ± 0.11 N for cardioverter-defibrillators (range 0.86-1.38 N) when exposed to the magnetic field.

CONCLUSION

Exposure of pacemakers or implantable cardioverter-defibrillators to a magnetic field of 0.1 T does not result in a force exceeding the regulatory demanded 5 N that could damage the connected leads.

Accurate guidance of a catheter by ultrasound imaging and identification of a catheter tip by pulsed-wave Doppler

BACKGROUND

With the advent of numerous minimally invasive medical procedures, accurate catheter guidance has become imperative. We introduce and test an approach for catheter guidance by ultrasound imaging and pulsed-wave (PW) Doppler.

METHODS

A steerable catheter is fitted with a small piezoelectric crystal at its tip that actively transmits signals driven by a function generator. We call this an active-tip (AT) catheter. In a water tank, we immersed a "target" crystal and a rectangular matrix of four "reference" crystals. Two-dimensional (2D) ultrasound imaging was used for initial guidance and visualization of the catheter shaft, and then PW Doppler mode was used to identify the AT catheter tip and guide it to the simulated target that was also visible in the 2D ultrasound image. Ten guiding trials were performed from random initial positions of the AT catheter, each starting at approximately 8 cm from the target.

RESULTS

After the ten navigational trials, the average final distance of the catheter tip from the target was 2.4 ± 1.2 mm, and the range of distances from the trials was from a minimum of 1.0 mm to a maximum of 4.5 mm.

CONCLUSIONS

Although early in the development process, these quantitative in vitro results show promise for catheter guidance with ultrasound imaging and tip identification by PW Doppler.

Right-side RF ablation using remote catheter navigation: experimental results in vivo

INTRODUCTION

The close proximity between the interventionalist and patient during catheter-based interventions for cardiac arrhythmia exposes the interventionalist to harmful radiation. A prototype remote catheter navigation system (RCNS) has been developed to reduce occupational dose. The safety, feasibility of this RCNS and a comparison of remote and conventional navigation techniques is investigated in vivo.

METHODS

Seven anatomical locations in the right side of the heart in porcine models were chosen as navigation targets. Using fluoroscopy and electrogram analysis, an experienced electrophysiology interventionalist manipulated a radiofrequency (RF) ablation catheter to each target using the RCNS and conventional navigation. Success rate, navigation time, exposure, exposure time and procedure time was recorded for all anatomical targets. Time to integrate the RCNS with the procedure suite was also measured.

RESULTS

All targets were successfully reached with the RCNS and conventional navigation. No erratic catheter motion was observed with the RCNS whereas 1 operation failure occurred. The anatomical targets were found to have the largest effect on navigation time (P < 0.05), exposure (P < 0.05), and exposure time (P < 0.01), although the navigation method had little to no effect on the metrics. These results suggest that remote navigation procedures can be performed with navigation times comparable to conventional bedside navigation.

CONCLUSION

Remote navigation with the RCNS may present a safe method of reducing occupational dose, while providing comparable navigation time with conventional bedside navigation.

Comparison of magnetic navigation system and conventional method in catheter ablation of atrial fibrillation: is magnetic navigation system is more effective and safer than conventional method?

BACKGROUND AND OBJECTIVES

Although there have been so many reports of catheter ablation of atrial fibrillation (AF) with magnetic navigation system (MNS), it is not necessarily obvious that MNS is more effective than conventional ablation. We performed AF ablation with MNS and compared the clinical outcomes and radiofrequency ablation parameters with those of conventional ablation.

SUBJECTS AND METHODS

One hundred eleven consecutive patients (conventional group, n=70 vs. MNS group, n=41) undergoing catheter ablation of AF were enrolled. We compared and analyzed the procedural parameters, namely fluoroscopic time, procedural time, acute procedural success and 3 months success rate of both groups.

RESULTS

The MNS group was associated with slightly larger left atrial size (43.7±6.3 mm vs. 41.2±6.3 mm, p=0.04), significantly longer total procedure time (352±50 minutes vs. 283±75 minutes, p<0.0001), and shorter total fluoroscopic time (99±28 minutes vs. 238±45 minutes, p<0.0001) than the conventional group. The MNS and conventional group did not differ with respect to acute procedural success, AF recurrence, atrial flutter/atrial tachycardia recurrence, or total arrhythmia recurrence. While no complications were observed in the MNS group, eight cases of significant pericardial effusion occurred in the conventional group.

CONCLUSION

The MNS system seems to be effective and safe in the catheter ablation of AF, particularly in the population of patients with persistent AF and slightly dilated left atria.

The magnetic navigation system allows safety and high efficacy for ablation of arrhythmias

Aims

We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities.

Methods and results

In this study, 610 consecutive patients underwent ablation. Patients were divided into two age- and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15 ± 9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P = 0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P = 0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P = ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P < 0.05). Less fluoroscopy was used in group MNS (30 ± 20 vs. 35 ± 25 min, P < 0.01). There were no differences in procedure times and recurrence rates for the overall groups (168 ± 67 vs. 159 ± 75 min, P = ns; 14 vs. 11%, P = ns; respectively).

Conclusions

Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs.

[Magnetic navigation for ablation of cardiac arrhythmias]

BACKGROUND

The first use of magnetic navigation for radiofrequency ablation of supraventricular tachycardias, was published in 2004. Subsequently, the method has been used for treatment of most types of tachyarrhythmias. This paper provides an overview of the method, with special emphasis on usefulness of a new remote-controlled magnetic navigation system.

MATERIAL AND METHODS

The paper is based on our own scientific experience and literature identified through a non-systematic search in PubMed.

RESULTS

The magnetic navigation system consists of two external electromagnets (to be placed on opposite sides of the patient), which guide an ablation catheter (with a small magnet at the tip of the catheter) to the target area in the heart. The accuracy of this procedure is higher than that with manual navigation. Personnel can be quickly trained to use remote magnetic navigation, but the procedure itself is time-consuming, particularly for patients with atrial fibrillation. The major advantage is a considerably lower radiation burden to both patient and operator, in some studies more than 50 %, and a corresponding reduction in physical strain on the operator. The incidence of procedure-related complications seems to be lower than that observed with use of manually operated ablation catheters. Work is ongoing to improve magnetic ablation catheters and methods that can simplify mapping procedures and improve efficacy of arrhythmia ablation. The basic cost for installing a complete magnetic navigation laboratory may be three times that of a conventional electrophysiological laboratory.

INTERPRETATION

The new magnetic navigation system has proved to be applicable during ablation for a variety of tachyarrhythmias, but is still under development.

Remote navigation guided ablation of incessant atrial tachycardia in a patient with restricted venous access

We report a case of a 45-year-old man with incessant supraventricular tachycardia (SVT) in the setting of intrahepatic inferior vena cava thrombus and a left upper extremity arteriovenous fistula. A diagnostic electrophysiology study (EPS) was performed via the right internal jugular and right subclavian veins. After confirming the mechanism of SVT was atrial tachycardia (AT), mapping, and successful ablation was performed using remote catheter navigation. This case demonstrates that remote navigation can facilitate the therapy of complex arrhythmias in challenging clinical situations.