Initial Experience with Catheter Ablation Using Remote Magnetic Navigation in Adults with Complex Congenital Heart Disease and in Small Children

Robotic magnetic-guided catheter ablation in patients with congenital heart disease: a systematic review and pooled analysis

BACKGROUND

Robotic magnetic navigation (RMN) has emerged as a potential solution to overcome challenges associated with catheter ablation of arrhythmias in patients with congenital heart disease (CHD).

OBJECTIVES

To assess safety and efficacy of RMNguided catheter ablation in patients with CHD.

DESIGN AND METHODS

A systematic review and pooled analysis was conducted on patients with CHD who underwent RMNguided catheter ablation. Random effects models were used to generate pooled estimates with the inverse variance method used for weighting studies.

RESULTS

Twentyfour nonoverlapping records included 167 patients with CHD, mean age 36.5 years, 44.6% female. Type of CHD was simple in 27 (16.2%), moderate in 32 (19.2%), and complex in 106 (63.5%). A total of 202 procedures targeted 260 arrhythmias, the most common being macroreentrant atrial circuits. The mean procedural duration was 207.5 minutes, with a mean fluoroscopy time of 12.1 minutes. The pooled acute success rate was 89.2% [95% CI (77.8%, 97.4%)]. Freedom from arrhythmia recurrence was 84.5% [95% CI (72.5%, 94.0%)] over a mean follow-up of 24.3 months. The procedural complication rate was 3.5% with no complication attributable to RMN technology.

CONCLUSION

RMN-guided ablation appears to be safe and effective across a variety of arrhythmia substrates and types of CHD.

ALARA in Pediatric Electrophysiology Laboratory

The effects of radiation on patients and the providers are dose-dependent and cumulative. Pediatric patients are not only more sensitive to radiation but also may undergo more procedures and diagnostic tests throughout their lifetime. As providers, the endeavor is to cause no harm and it behooves us to either eliminate or minimize the radiation exposure to patients without affecting the efficacy and outcomes of the diagnostic or therapeutic modalities. Pediatric electrophysiologists have taken the lead in attempting to minimize the radiation exposure to patients and staff with innovative and advanced techniques. The techniques range from minimizing the exposure to radiation with better understanding and applications of the physics associated with fluoroscopic imaging to using alternative imaging modalities that do not use radiation.

The First Evaluation of Remote Magnetic Navigation-Guided Pediatric Ventricular Arrhythmia Ablation

Catheter ablation (CA) is an important treatment option for ventricular arrhythmias (VA) in pediatric cardiology. Currently, various CA techniques are available, including remote magnetic navigation (RMN)-guided radiofrequency (RF) ablation. However, no studies evaluate RMN-guided ablative therapy outcomes in children with VA yet. This study aimed to compare procedural and long-term outcomes between RMN-guided and manual (MAN)-guided VA ablation in children. This single-center, retrospective study included all CA procedures for VA performed in children with or without structural heart disease from 2008 until 2020. Two study groups were defined by CA technique: RMN or MAN. Primary outcome was recurrence of VA. Baseline clinical, procedural and safety data were also evaluated. This study included 22 patients, who underwent 30 procedures, with a median age of 15 (IQR 14-17; range 1-17) years and a mean weight of 57 ± 20 kg. In total, 14 procedures were performed using RMN and 16 using MAN (22 first and 8 redo procedures). Regarding first procedures, recurrence rates were significantly lower in RMN compared to MAN (20% versus 67%, P = 0.029), at a mean follow-up of 5.2 ± 3.0 years. Moreover, fluoroscopy dosages were significantly lower in RMN compared to MAN [20 (IQR 14-54) versus 48 (IQR 38-62) mGy, P = 0.043]. In total, 20 patients (91%) were free of VA following their final ablation procedure. This is the first study to investigate the use of RMN in pediatric VA ablation. RMN showed improved outcomes compared to MAN, resulting in lower VA recurrence and reduced fluoroscopy exposure.

Remote magnetic navigation shows superior long-term outcomes in pediatric atrioventricular (nodal) tachycardia ablation compared to manual radiofrequency and cryoablation

Background

Catheter ablation (CA) is the first-choice treatment for tachyarrhythmia in children. Currently available CA techniques differ in mechanism of catheter navigation and energy sources. There are no large studies comparing long-term outcomes between available CA techniques in a pediatric population with atrioventricular reentry tachycardia (AVRT) or atrioventricular nodal reentry tachycardia (AVNRT) mechanisms.

Objective

This study aimed to compare procedural and long-term outcomes of remote magnetic navigation-guided radiofrequency (RF) ablation (RMN), manual-guided RF ablation (MAN) and manual-guided cryoablation (CRYO).

Methods

This single-center, retrospective study included all first consecutive CA procedures for AVRT or AVNRT performed in children without structural heart disease from 2008 to 2019. Three study groups were defined by the ablation technique used: RMN, MAN or CRYO. Primary outcome was long-term recurrence of tachyarrhythmia.

Results

In total, we included 223 patients, aged 14 (IQR 12-16) years; weighting 56 (IQR 47-65) kilograms. In total, 108 procedures were performed using RMN, 76 using MAN and 39 using CRYO. RMN had significantly lower recurrence rates compared to MAN and CRYO at mean follow-up of 5.5 ± 2.9 years (AVRT: 4.3% versus 15.6% versus 54.5%, P < 0.001; AVNRT: 7.7% versus 8.3% versus 35.7%, P = 0.008; for RMN versus MAN versus CRYO respectively). In AVNRT ablation, RMN had significantly lower fluoroscopy doses compared to CRYO [30 (IQR 20-41) versus 45 (IQR 29-65) mGy, P = 0.040).

Conclusion

In pediatric patients without structural heart disease who underwent their first AV(N)RT ablation, RMN has superior long-term outcomes compared to MAN and CRYO, in addition to favorable fluoroscopy doses.

Robot-assisted mandibular angle osteotomy using electromagnetic navigation

BACKGROUND

To explore the potential of electromagnetic (EM) navigation technology in the field of robot-assisted surgery, we set up a maxillofacial surgical robotic system (MSRS) guided by an EM navigation tool. Mandibular angle osteotomy was used to analyze the feasibility in confined surgical areas.

METHODS

Model and animal experiments were implemented to validate the system precision. Before the experiment, a customized dental splint was made and then fixed with a standard navigation part. An accurate 3D surgical plan was designed based on the preoperative CT scan. During the experiment, the splint was rigidly mounted on teeth for navigation registration, so the robot could position a specially designed template to guide the accurate osteotomy according to the preoperative plan. For the model experiment, a Coordinate Measuring Machine was used to measure the template's position and angle. For the animal experiment, surgeons completed the surgery by moving a saw along the template, while a postoperative CT scan was carried out to calculate the precision.

RESULTS

All procedures were successfully completed, with no complications in any of the experimental animals. In the model experiment, the accuracy of the navigation position and angle was 0.44±0.19 mm and 3.5°±2.1°, respectively. In the animal experiment, the lateral osteotomy line error was 0.83±0.62 mm, the interior error was 1.06±1.03 mm, and the angle between the actual cutting plane and preoperative planning plane was 5.9°±4.7°.

CONCLUSIONS

Robot-assisted surgery with EM navigation resulted feasible in the real operating environment. Moreover, this system's precision could meet clinical needs, while the proposed procedure was safe and easy on animals. Consequently, this approach has the potential to be applied to clinical craniomaxillofacial practice in the near future.

Anatomical Substrates and Ablation of Reentrant Atrial and Ventricular Tachycardias in Repaired Congenital Heart Disease

Advances in surgical repair techniques for various types of congenital heart disease have improved survival into adulthood over the past decades, thus exposing these patients to a high risk of atrial and ventricular arrhythmias later in life. These arrhythmias arise from complex arrhythmogenic substrates. Substrate formation may depend on both pathological myocardial remodelling and variable anatomical boundaries, determined by the type and timing of prior corrective surgery. Accordingly, arrhythmogenic substrates after repair have changed as a result of evolving surgical techniques. Radiofrequency catheter ablation offers an important therapeutic option but remains challenging due to the variable anatomy, surgically created obstacles and the complex arrhythmogenic substrates. Recent technical developments including electroanatomical mapping and image integration for delineating the anatomy facilitate complex catheter ablation procedures. The purpose of this review is to provide an update on the changing anatomical arrhythmogenic substrates and their potential impact on catheter ablation in patients with repaired congenital heart disease and tachyarrhythmias.

[Arrhythmia in adults with congenital heart defects : Atrial tachycardia]

Atrial arrhythmias are frequently encountered in patients with congenital heart disease (CHD) with or without corrective surgery and respond to pharmacological therapies with only limited success. This review describes the technologies currently available for performing successful ablation procedures in this very complex patient cohort. In addition to an understanding of the underlying anatomy, which can be supplemented by 3D imaging with the aid of magnetic resonance imaging (MRI) or computed tomography (CT), the choice between the different 3D mapping systems (sequential versus simultaneous) is presented. Finally, conventional manual navigation is compared with magnetic navigation and then discussed with regard to the respective arrhythmias encountered with the different forms of CHD.

Optimizing contact force during ablation of atrial fibrillation: available technologies and a look to the future

In a select atrial fibrillation population, catheter ablation is considered first-line therapy. Prevention of early reconnection of the isolated pulmonary veins is an important goal for a successful treatment. Here, adequate catheter–tissue contact is crucial. One of the most promising new advances, therefore, is contact force (CF) sensing technology. The aim of this review is to provide an overview of innovations regarding catheter ablation of atrial fibrillation with a special focus on CF optimization. Both experimental and human studies show how CF sensing catheters lead to a reduction of fluoroscopy time, increased procedural safety and a better clinical outcome. Possible future developments include new parameters combining real-time ablation data, direct visualization of lesion formation and incorporation of robotics.

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.

Retrograde access of the left atrium for pulmonary vein isolation using magnetic navigation after closure of an atrial septum defect

Transseptal puncture is the most commonly used technique to perform electrophysiological procedures in the left atrium. This case report describes a pulmonary vein isolation in a patient with a paroxysmal atrial fibrillation, complicated by the presence of an oversized Amplatzer device (AGA Medical Corp., Golden Valley, MN). A retrograde approach using the magnetic navigation system (Niobe, Stereotaxis Inc., St Louis, USA) was performed, and showed to provide a feasible, safe and successful alternative for catheter ablation of cardiac arrhythmias in patients in whom the classic transseptal approach is impossible.

Catheter ablation in children and young adults: is there an additional benefit from remote magnetic navigation?

Purpose

Although rare, children and young adults can suffer from significant cardiac arrhythmia, especially in the context of congenital malformations and after cardiac surgery.

Methods

A total of 62 patients (32 female, median age 20 years) underwent an invasive electrophysiology study between 2008–2011: half had normal cardiac anatomy, whereas the remaining patients had various types of congenital heart disease. All patients were treated using either conventional techniques (CVN) or remote magnetic navigation (RMN).

Results

Patients treated with the RMN system differed substantially from patients in the CVN group with respect to presence of congenital heart disease (67 % vs. 37 %), previous cardiac surgery (59 % vs. 20 %) or failed previous conventional ablation (22 % vs. 9 %), respectively. Although these more complex arrhythmias resulted in longer median procedure duration (180 vs. 130 min, p = 0.034), the median overall fluoroscopy exposure in the RMN group was significantly lower (4.1 vs. 5.2 min, p = 0.020). Clinical outcome was comparable in both groups without complications caused by the ablation.

Conclusions

Catheter ablation using remote magnetic navigation is safe and feasible in children and young adults and is especially valuable in patients with abnormal cardiac morphologies. RMN resulted in significantly lower radiation exposure compared with the conventional technique.

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.

Magnetic Versus Manual Catheter Navigation for Ablation of Free Wall Accessory Pathways in Children

Background—

Transcatheter ablation of accessory pathway (AP)–mediated tachycardia is routinely performed in children. Little data exist regarding the use of magnetic navigation (MN) and its potential benefits for ablation of AP-mediated tachycardia in this population.

Methods and Results—

We performed a retrospective review of prospectively gathered data in children undergoing radiofrequency ablation at our institution since the installation of MN (Stereotaxis Inc, St. Louis, MO) in March 2009. The efficacy and safety between an MN-guided approach and standard manual techniques for mapping and ablation of AP-mediated tachycardia were compared. During the 26-month study period, 145 patients underwent radiofrequency ablation for AP-mediated tachycardia. Seventy-three patients were ablated with MN and 72 with a standard manual approach. There were no significant differences in demographic factors between the 2 groups with a mean cohort age of 13.1±4.0 years. Acute success rates were equivalent with 68 of 73 (93.2%) patients in the MN group being successfully ablated versus 68 of 72 (94.4%) patients in the manual group ( P =0.889). During a median follow-up of 21.4 months, there were no recurrences in the MN group and 2 recurrences in the manual group ( P =0.388). There were no differences in time to effect, number of lesions delivered, or average ablation power. There was also no difference in total procedure time, but fluoroscopy time was significantly reduced in the MN group at 14.0 (interquartile range, 3.8–23.9) minutes compared with the manual group at 28.1 (interquartile range, 15.3–47.3) minutes ( P <0.001). There were no complications in either group.

Conclusions—

MN is a safe and effective approach to ablate AP-mediated tachycardia in children.

Acute and long-term outcomes of catheter ablation using remote magnetic navigation in patients with congenital heart disease

The aim of the present study was to assess the feasibility, safety, and long-term results of remote magnetic navigation in arrhythmias associated with complex congenital heart disease (CHD). The improved outcomes for CHD resulted in an increased number of complex arrhythmias requiring distinctive ablation techniques. Thirty-six patients with CHD (age 35 ± 19 years, 21 male) were divided into 3 complexity groups and underwent 43 radiofrequency catheter ablation procedures using the magnetic navigation system (including 7 redo ablations) in combination with the CARTO RMT system. A total of 59 tachyarrhythmias were identified. Most patients had surgical scar-related tachycardia (25 focal, including 4 microreentrant atrial tachycardia, and 27 macroreentrant atrial tachycardia). Four accessory pathways and three ventricular tachycardias were diagnosed and treated. In 31 patients, ablation was successful, with an end point of noninducibility (86%). The success rate for CHD complexity of type I, II, and III was 50%, 88%, and 89%, respectively. The mean procedure and fluoroscopy time was 216 ± 101 minutes and 40 ± 34 minutes, respectively. The number of radiofrequency applications was 42 ± 47. No major complications related to the procedures occurred. Of the patients, 67% remained free of recurrence during a mean follow-up of 26 ± 4 months. Recurrence developed in 0%, 16%, and 45% of patients with CHD type I, II, and III, respectively. In conclusion, the magnetic navigation system is feasible to treat arrhythmias with reasonable success rates and good long-term outcomes in adult patients with CHD. The use of the magnetic navigation system offers advantages in complex anatomic situations.

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.

Remote magnetic navigation with irrigated tip catheter for ablation of paroxysmal atrial fibrillation

BACKGROUND

The remote magnetic navigation system (MNS) has been used with a nonirrigated magnetic catheter for atrial fibrillation (AF) ablation. The objective of this study was to evaluate the feasibility and efficiency of the newly available irrigated tip magnetic catheter for index pulmonary vein isolation (PVI) in patients with paroxysmal AF (PAF).

METHODS AND RESULTS

Between January 2008 and June 2009, 30 consecutive patients with drug-resistant PAF underwent circular mapping catheter-guided PVI with MNS (MNS group). The outcomes were compared retrospectively with those of a conventional hand-controlled ablation technique during the same period in 44 consecutive patients (manual group). All 4 pulmonary veins were successfully isolated in both groups except in 4 patients in the MNS group. Radiofrequency and procedure duration were higher in the MNS group (60 ± 27 versus 43 ± 16 minutes; P = 0.0019) than in the manual group (246 ± 50 versus 153 ± 51 minutes; P < 0.0001). In the patients who underwent only PVI, total fluoroscopic time also was longer in the MNS group than in the manual group (58 ± 24 versus 40 ± 14 minutes; P = 0.0002). At 12-month follow-up after a single procedure, 69.0% of the patients in MNS group and 61.8% of patients in manual group were free of atrial tachyarrhythmia without antiarrhythmic drugs. There was no significant difference in the atrial tachyarrhythmia-free survival between the 2 groups (P = 0.961). Cardiac tamponade occurred in 1 patient in the manual group.

CONCLUSIONS

In patients with PAF, MNS-guided PVI with the newly available irrigated tip magnetic catheter backed up with manual ablation whenever required is feasible. However, it requires longer ablation, fluoroscopy, and procedural times than the conventional approach in the early experience stage.

Effect of magnetic navigation system on procedure times and radiation risk in children undergoing catheter ablation

Transcatheter ablation is an effective method to eliminate the arrhythmogenic substrate in symptomatic children with various types of arrhythmias. A reduction in the procedure and fluoroscopy time would decrease the hazardous effects of the ablation procedures. The magnetic navigation system (MNS) uses atraumatic catheters and facilitates accurate catheter placement in all regions of the heart for mapping and therapy delivery. We compared the efficacy and safety between a manual and MNS-guided approach for mapping and ablation of arrhythmias in a general pediatric arrhythmia population and in a subgroup of young children aged <10 years old. A total of 58 pediatric patients (mean age 12.2 +/- 3.2 years) were included in the present study. Of the 58 consecutive patients, 29 were treated with the MNS and 29 underwent conventional manual ablation. No demographic differences were present between the 2 groups. Acute success was achieved in 26 of 29 patients and 27 of 29 patients (p = NS). The mean procedure and fluoroscopy times were comparable in both study groups (168 +/- 56 minutes vs 183 +/- 52 minutes, p = NS; and 22 +/- 59 minutes vs 30 +/- 29 minutes, p = NS). In young children (aged <10 years), the success rate did not differ between the 2 groups (10 of 11 vs 6 of 8, p = NS). However, significant decreases in the procedure and fluoroscopy times were achieved (139 +/- 57 minutes vs 204 +/- 49 minutes and 13 +/- 7 minutes vs 31 +/- 28 minutes, respectively; p = 0.01 and p = 0.04). In conclusion, our data have strongly suggested that using the MNS for treating young children is advantageous, because it significantly reduced the procedure and fluoroscopy times without compromising efficacy.

Mapping of atrial tachycardia by remote magnetic navigation in postoperative patients with congenital heart disease

OBJECTIVES

The purpose of this study was to investigate if remote magnetic navigation (RMN) offers a reduction of fluoroscopy time when used for atrial tachycardia (AT) mapping in a spectrum of patients with congenital heart disease (CHD) after "simple" or "complex" atrial surgery.

BACKGROUND

Data about AT mapping using RMN in larger populations of patients with CHD are scarce.

METHODS

RMN in combination with electroanatomic mapping was used for AT mapping in 22 patients. According to anatomic complexity, patients were classified into 3 groups: Group 1: patients after minor atrial surgery (n = 7); Group 2: patients after the Fontan operation (n = 9); and group 3: patients after the Senning/Mustard operation (n = 6).

RESULTS

Atrial mapping with a nonirrigated tip RMN catheter was completed successfully in all patients. In Group 1 no significant reduction in fluoroscopy time was noticed over time (mean fluoroscopy time 7.9 minutes). In the 15 patients of group 2 and group 3 with complex CHD, the fluoroscopy time for mapping in the last 9 patients (6.4 +/- 2.8 minutes) was significantly shorter than in the first 6 patients (29.7 +/- 10.5 minutes, P < 0.0001). Acutely successful ablation was achieved in 21 of 22 patients (97%) using the RMN catheter (n = 3) or a conventional catheter (n = 18) without procedural complications.

CONCLUSIONS

RMN for AT mapping in patients with complex atrial anatomy leads to a significant reduction of fluoroscopy time.