Remote Magnetic Navigation Group Research Articles

Troponin T release comparing manually or magnetically guided radiofrequency ablation for AVNRT- a MAGMA AVNRT substudy

Objectives. Catheter ablation is regarded as first-line therapy for symptomatic atrioventricular nodal reentry tachycardia (AVNRT). Ablation induces intended myocardial damage and the extent of myocardial damage may differ between ablation methods. The objective of this MAGMA AVNRT(NCT00875914) substudy was to compare high-sensitive cardiac troponin T (hs-cTnT) levels as a surrogate marker for myocardial damage after manually guided (MAN) AVNRT ablation versus AVNRT ablation using remote magnetic navigation (RMN). Design. In total, 70 patients (mean age 44 ± 14 years, 26% male) undergoing catheter ablation for AVNRT in the MagMa-AVNRT-Trial were randomized to remote magnetic navigation (n = 34, 49%) or manually guided catheter ablation (n = 36, 51%). hs-cTnT was measured the day after the procedure. Results. The median follow-up time was 6.2 ± 1.1 years. Acute success was 100% in both groups. hs-cTnT release was significantly lower in the remote magnetic navigation group (52 ng/L versus 95 ng/L, p < .01), even though the ablation time was longer and number of applications was higher with remote magnetic navigation (4.2 min vs 2.8 min, p = .017; 4.9 vs 3.3 applications, p = .01). hs-cTnT released per minute ablation time was also lower with remote magnetic navigation (12 ng/L versus 34 ng/L, p < .01). Both groups exhibited similar clinical long-term follow up regarding recurrence and complications. Conclusion. Remote magnetic navigation controlled catheter ablation of AVNRT has similar clinical outcome, but leads to less hs-cTnT release than manually guided catheter ablation. This might correspond to less unintended myocardial damage with RMN, which might be advantageous in complex ablation procedures.

Remote magnetic navigation facilitates the ablations of frequent ventricular premature complexes originating from the outflow tract and the valve annulus as compared to manual control navigation

ObjectiveThe purpose of this study was to assess the role of remote magnetic navigation (RMN) in the ablation of ventricular premature complexes (VPCs) arising from outflow tracts (OT) and valve annuli by comparing to manual control navigation (MCN). MethodsA total of 152 patients with frequent VPCs were prospectively enrolled. 64 (42%) patients underwent ablation guided by RMN. Acute success rate was defined as the complete elimination and non-inducibility of clinical VPCs during the procedure. ResultsOverall, acute success rate of RMN group was not different from MCN group (87.5% vs 84.1%, p = 0.56). Compared to MCN group, the fluoroscopic time of OT-VPCs ablation in the RMN group was significantly reduced by 67% (2.9 ± 2.3 min vs 8.9 ± 9.7 min, p = 0.006), and the ablation applications in successful cases were significantly reduced (11 ± 7 vs 15 ± 11, p = 0.018). Compared to MCN, RMN significantly decreased ablation applications (15 ± 9 vs 23 ± 9, p = 0.013) in the acute success rates of ablating VPCs of valve annulus, and has a trend of a higher success rate for VPCs arising from tricuspid annulus (10/11 vs 7/12, p = 0.193). No complications occurred in the RMN group. Three cases of cardiac tamponade and one case of transient atrioventricular block occurred in the MCN group (p = 0.22). After a mean follow up of 16.2 months, 2/56 and 3/74 patients had a recurrence of VPCs in the RMN group and MCN group respectively (p = 0.75). ConclusionsWhen compared to MCN, RMN-guided ablation for VPCs was just as effective and safe, with the added benefit of reduced fluoroscopic time and fewer ablation applications.

A comparative analysis of clinical outcomes and disposable costs of different catheter ablation methods for the treatment of atrioventricular nodal reentrant tachycardia.

BackgroundCatheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) is a commonly performed electrophysiology (EP) procedure. Few data exist comparing conventional (CONV) versus novel ablation strategies from both clinical and direct cost perspectives. We sought to investigate the disposable costs and clinical outcomes associated with three different ablation methodologies used in the ablation of AVNRT.MethodsWe performed a retrospective review of AVNRT ablations performed at Augusta University Medical Center from 2006 to 2014. A total of 183 patients were identified. Three different ablation techniques were compared: CONV manual radiofrequency (RF) (n=60), remote magnetic navigation (RMN)-guided RF (n=67), and cryoablation (CRYO) (n=56).ResultsBaseline demographics did not differ between the three groups except for a higher prevalence of cardiomyopathy in the RMN group (p<0.01). The clinical end point of interest was recurrent AVNRT following the index ablation procedure. A significantly higher number of recurrent AVNRT cases occurred in the CRYO group as compared to CONV and RMN (p=0.003; OR =7.75) groups. Cost-benefit analysis showed both CONV and RMN to be dominant compared to CRYO. Cost-minimization analysis demonstrated the least expensive ablation method to be CONV (mean disposable catheter cost = CONV US$2340; CRYO US$3515; RMN US$5190). Despite comparable clinical outcomes, the incremental cost of RMN over CONV averaged US$3094 per procedure.ConclusionAVNRT ablation using either CONV or RMN techniques is equally effective and associated with lower AVNRT recurrence rates than CRYO. CONV ablation carries significant disposable cost savings as compared to RMN, despite similar efficacy.

Multicenter, randomized comparison between magnetically navigated and manually guided radiofrequency ablation of atrioventricular nodal reentrant tachycardia (the MagMa-AVNRT-trial).

Remote magnetic navigation (RMN) is attributed to diminish radiation exposure for both patient and operator performing catheter ablation for different arrhythmia substrates. The purpose of this prospective, randomized study was to compare RMN with manually guided catheter ablation for AV nodal reentrant tachycardia (AVNRT) regarding fluoroscopy time/dosage, acute and long-term efficacy as well as safety. A total of 218 patients with AVNRT undergoing catheter ablation at three centers (male 34%, mean age 50±17years) were randomized to a manual approach (n=113) or RMN (n=105) using the Niobe® magnetic navigation system. The primary study endpoint was total fluoroscopy time/dosage for patient and operator at the end of the procedure. Secondary endpoints included acute success, procedure duration, complications and success rate after 6months. Fluoroscopy time and dosage for the patient were significantly reduced in the RMN group compared to the manual group (6±6 vs. 11±10min; p<0.001 and 425±558 vs. 751±900 cGycm2, p=0.002). A reduction in fluoroscopy time/dose also applied to the operator (3±5 vs. 7±9min 209±444 vs. 482±689 cGycm2, p<0.001). Procedure duration was significantly longer in the RMN group (88±29 vs. 79±29min; p=0.03) and crossover from the RMN group to manual ablation occurred in 7.6% of patients (7.6 vs. 0.1%; p=0.02). Acute success was achieved in 100% of patients in both groups. Midterm success after 6months was 97 vs. 98% (p=0.67). No complications occurred in both groups. The use of RMN for catheter ablation of AVNRT compared to a manual approach results in a reduction of fluoroscopy time and dosage of about 50% for both patients and physicians. Acute and midterm success and safety are comparable. RMN is a good alternative to a manual approach for AVNRT ablation.

Abstract 14384: Scar Homogeneization Ablation in Patients With Ischemic Cardiomyopathy: Comparison Between Remote Magnetic Navigation and Manual Ablation

Introduction: Remote magnetic navigation (RMN) and ablation with the magnetic irrigated tip catheter has been reported as a feasible and safe technique for the treatment of ventricular arrhythmias (VA). We compared the procedural benefit and the outcomes of patients with ischemic cardiomyopathy (IC) undergoing VAs ablation with the RMN versus the manual approach. Methods: Consecutive pts with IC undergoing VAs ablation both with RMN and with manual ablation at different Institutions were enrolled. Substrate mapping and ablation technique with scar homogenization were utilized for ablation with the end point of elimination of all abnormal electrograms within and or around the scar area. Procedural data and outcomes were analyzed. Post-ablation pacing maneuvers and isoproterenol were used to verify Vas inducibility. Results: A total of 218 consecutive pts (85.3% male, 69.2±7.7 years, LVEF 30.6±8.2) with IC were included with 80 pts undergoing manual ablation while 138 pts underwent RMN ablation. Patients with a scar size &lt; 60 cm2 at the 3D voltage mapping system were excluded. The mean scar size was 140 ± 61 cm2. VT was inducible in 83% pts with a cycle length of 352.1±70.7 msec. The density of the substrate map was higher in the RMN group when compared to the manual ablation group (553±118 vs 347±97, p&lt;0.001). Acute ablation success was achieved in 217 (99.5%) of pts. The mean procedural duration and fluoroscopy time was 255.8±116.6 min and 34.8±22.9 min respectively. The mean mapping time was lower in the RMN group (80.3 ± 13.8 min) compared to the manual ablation group (96.1 ± 20.3 minutes, p &lt; 0.001), while the radiofrequency time was lower in the manual ablation group(66.1 ± 27.3 min vs. 74.4 ± 20.7 min, p=0.02). At 15.4±6.8 months follow-up the success rate in the RMN group was 81.2% (112) while in the manual ablation group 55 (69%) pts were recurrence free (p=0.037). There was one pericardial tamponade which required pericardiocentesis in the manual ablation group. Conclusion: This study shows that VAs ablation using RMN in pts with IC and a scar size greater than 60 cm2 increases success rate at follow up when compared to manual ablation. The better outcome might be due to the higher amount of time dedicated to RF applications to achieve scar homogenization rather than mapping

Abstract 9860: Safety and Clinical Outcome of Catheter Ablation of Ventricular Arrhythmias Using Contact Force Sensing, Consecutive Case Series

Introduction: Poor catheter-to-myocardial contact can lead to ineffective ablation lesions and suboptimal outcome. Contact force (CF) sensing catheters in ventricular tachycardia (VT) ablations has not been studied for their long term efficacy. Hypothesis: The hypothesis is that CF ablation is superior to manual ablation (MAN) and non-inferior to remote magnetic navigation (RMN) ablation for safety and efficacy in acute and long term outcome. Methods: A total of 249 consecutive patients underwent VT ablation, with the use of MAN, CF or RMN catheters were included in this single center cohort study from January 2007 until March 2014. The primary endpoints were procedural success, acute major complications and VT recurrences at follow-up. The average follow-up period was ± 20 months. Results: Acute success was achieved in 191 out of 249 procedures (75.9%). Acute success in manual ablation, CF ablation and RMN ablation was 70.1%, 72.3% and 85.2% respectively (P = 0.038). Major complications occurred in 3.2% and there was a trend towards less major complications (P = 0.055) in the RMN group. Thirty-six percent of the patients with an initially successful procedure had a recurrence during follow-up (CF 41.2% MAN 37.5% RMN 32.0% P = NS). Conclusions: The use of CF sensing catheters does not improve the procedural outcome or safety profile in comparison to non-CF sensing ablation in ventricular arrhythmias. RMN non-CF sensing ablation has the highest procedural success rate. Future studies are necessary to investigate the role of CF in VT ablation and to define the optimal force.

Safety and Clinical Outcome of Catheter Ablation of Ventricular Arrhythmias Using Contact Force Sensing: Consecutive Case Series.

Poor catheter-to-myocardial contact can lead to ineffective ablation lesions and suboptimal outcome. Contact force (CF) sensing catheters in ventricular tachyarrhythmia (VT) ablations have not been studied for their long-term efficacy. The aim of this study was to compare CF ablation to manual ablation (MAN) and remote magnetic navigation (RMN) ablation for safety and efficacy in acute and long-term outcome. A total of 239 consecutive patients who underwent VT ablation with the use of MAN, CF, or RMN catheters were included in this single-center cohort study from January 2007 until March 2014. The primary endpoints were procedural success, acute major complications, and VT recurrences at follow-up. The median follow-up period was 25 months. Acute success was achieved in 182 out of 239 procedures (76%). Acute success in manual ablation, CF ablation and RMN ablation was 71%, 71%, and 86%, respectively (P = 0.03). Major complications occurred in 3.3% and there were less major complications (P = 0.04) in the RMN group. After an initial successful procedure, 66 of 182 patients (36%) had a recurrence during follow-up. This was not significantly different between groups. Using an intention-to-treat analysis, 124 patients (52%) had a recurrence. The recurrence rate was lowest in the RMN group. The use of CF sensing catheters did not improve procedural outcome or safety profile in comparison to non-CF sensing ablation in this observational study of ventricular arrhythmia ablations.

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

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. 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. 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). 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.

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

PurposeAlthough rare, children and young adults can suffer from significant cardiac arrhythmia, especially in the context of congenital malformations and after cardiac surgery.MethodsA 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).ResultsPatients 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.ConclusionsCatheter 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.

Remote magnetic with open-irrigated catheter vs. manual navigation for ablation of atrial fibrillation: a systematic review and meta-analysis

The aim of this study was to determine the efficacy and safety of remote magnetic navigation (RMN) with open-irrigated catheter vs. manual catheter navigation (MCN) in performing atrial fibrillation (AF) ablation. We searched in PubMed (1948-2013) and EMBASE (1974-2013) studies comparing RMN with MCN. Outcomes considered were AF recurrence (primary outcome), pulmonary vein isolation (PVI), procedural complications, and data on procedure's performance. Odds ratios (OR) and mean difference (MD) were extracted and pooled using a random-effect model. Confidence in the estimates of the obtained effects (quality of evidence) was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. We identified seven controlled trials, six non-randomized and one randomized, including a total of 941 patients. Studies were at high risk of bias. No difference was observed between RMN and MCN on AF recurrence [OR 1.18, 95% confidence interval (CI) 0.85 to 1.65, P = 0.32] or PVI (OR 0.41, 95% CI 0.11-1.47, P = 0.17). Remote magnetic navigation was associated with less peri-procedural complications (Peto OR 0.41, 95% CI 0.19-0.88, P = 0.02). Mean fluoroscopy time was reduced in RMN group (-22.22 min; 95% CI -42.48 to -1.96, P = 0.03), although the overall duration of the procedure was longer (60.91 min; 95% CI 31.17 to 90.65, P < 0.0001). In conclusion, RMN is not superior to MCN in achieving freedom from recurrent AF at mid-term follow-up or PVI. The procedure implies less peri-procedural complications, requires a shorter fluoroscopy time but a longer total procedural time. For the low quality of the available evidence, a proper designed randomized controlled trial could turn the direction and the effect of the dimensions explored.

Long‐Term Efficacy of Single Procedure Remote Magnetic Catheter Navigation for Ablation of Ischemic Ventricular Tachycardia: A Retrospective Study

Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long-term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open-irrigated-tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long-term success as freedom from VT upon follow-up. There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long-term success in RMN group: after a median of 13 (range 1-34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long-term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time.

Remote magnetic versus manual catheter navigation for circumferential pulmonary vein ablation in patients with atrial fibrillation

BackgroundOnly limited data exist on the clinical utility of remote magnetic navigation (RMN) for pulmonary vein (PV) ablation. Aim of this prospective study was to evaluate the safety and efficacy of RMN for PV isolation as compared to the manual (CON) approach.Methods and resultsA total of 161 consecutive patients undergoing circumferential PV isolation were included. Open-irrigated 3.5 mm ablation catheters under the guidance of a mapping system were used. The catheter was navigated with the Stereotaxis Niobe II system in the RMN group (n = 107) and guided manually in the CON group (n = 54). Electrical isolation of all PVs was achieved in 90% of the patients in the RMN group and in 87% in the CON group (p = 0.6). All subjects were followed every 3 months by 7d Holter-ECG. At 12 months of follow-up, 53.5% (RMN) and 55.5% (CON) of the patients were free of any left atrial tachycardia/atrial fibrillation (AF) episode (p = 0.57). Free of symptomatic AF recurrence were 66.3% (RMN) and 62.1% (CON) of the subjects (p = 0.80). Use of RMN was associated with longer procedure duration (p < 0.0001), ablation times (p < 0.0001), and RF current application duration (p < 0.05). In contrast, fluoroscopy time was lower in the RMN group (p < 0.0001). Major complications occurred in 6 of 161 procedures (3.7%), with no significant difference between groups (p = 0.75).ConclusionRMN-guided PV ablation provides comparable acute and long-term success rates as compared to manual navigation. Procedural complication rates are similar. The use of RMN is associated with markedly reduced fluoroscopy time, but prolonged ablation and procedure duration.

Feasibility and Safety of Remote-Controlled Magnetic Navigation for Ablation of Atrial Fibrillation

Radiofrequency ablation for atrial fibrillation (AF) involves complex catheter manipulation resulting in prolonged procedure time and fluoroscopy exposure. Remote magnetic navigation (RMN) represents a novel approach toward improving the ability to perform complex ablation. Forty patients underwent ablation for AF, 20 using RMN (NIOBE II, Stereotaxis, Inc) with a 4-mm-tip magnetic catheter (Celsius, Biosense Webster) and 20 using a conventional 8-mm-tip bidirectional ablation catheter (Blazer, Boston Scientific). All patients underwent a combined wide area circumferential ablation and segmental pulmonary vein (PV) isolation using a circular mapping catheter and cavotricuspid isthmus ablation for right atrial flutter. The procedural end point was PV entrance block. There was no difference in atrial size, left ventricular systolic function, or type of AF between groups. PV entrance block was achieved in all patients. Mean procedure time was 279 +/- 60 minutes in the conventional group versus 209 +/- 56 minutes in the RMN group (p <0.001). Mean fluoroscopy time in the conventional group was 58.6 +/- 21 minutes versus 19.5 +/- 9.8 in the RMN group (p <0.001). At 1 year there were 15 patients in the conventional group and 16 in the RMN group free from clinical AF and off antiarrhythmic drugs (p = NS). There were 2 additional ablations performed for atypical atrial flutter in the conventional group and 3 in the RMN group (p = ns). Ablation catheter char formation was not observed. There were no procedural complications. In conclusion, radiofrequency ablation of AF performed with RMN is safe and feasible. Compared with conventional hand-navigated ablation, RMN ablation results in similar clinical outcomes with decreased fluoroscopy and procedure times.

Remote Magnetic Navigation‐Assisted Catheter Ablation Enhances Catheter Stability and Ablation Success with Lower Catheter Temperatures

It has been suggested that remote magnetic navigation (RMN) may provide enhanced catheter stability and substrate contact to aid in ablation. To date, no study has examined this claim. Accordingly, we compared the characteristics of the successful ablation of atrioventricular reentry tachycardia (AVNRT) using RMN with a matched population ablated using a conventional (CON) manual approach. Sixteen patients who underwent RMN-assisted ablation of typical AVNRT were matched with 16 patients who had a CON-AVNRT ablation. All patients had successful slow pathway modification without complication. The mean catheter temperature achieved with the successful ablation was significantly lower with RMN than with CON (42 +/- 7 degrees C vs 47 +/- 3 degrees C, P <or= 0.05). Time to junctional tachycardia (JT) was significantly earlier (5.7 +/- 4.1 s vs 11.2 +/- 8.9 s, P <or= 0.05) and variation in catheter temperature with the successful ablation (0.89 +/- 0.45 vs 1.45 +/- 0.49, P < 0.01) was significantly reduced in the RMN group than in the CON group. There was no significant difference between RMN and CON in terms of the total number of lesions and the mean power achieved during the successful lesion. Although the construction of the ablation catheters is similar, ablations with RMN catheters resulted in a lower mean temperature, earlier time to JT, and less variability of temperature during ablation, suggesting greater catheter stability. This study indicates that ablation with RMN can achieve success with lower catheter temperatures.