Remote Robotic Navigation Research Articles

48 * Factors affecting catheter contact in the human left atrium and their impact on ablation efficacy

Introduction: Pre-clinical work suggests factors including catheter orientation and contact consistency during individual radiofrequency ablations influence lesion size and that impedance drop during ablation correlates with the lesion size. Our aim was to investigate factors affecting catheter contact in the human left atrium (LA) and their effects on ablation. Methods and Results: 2,900 eight second static LA mapping points were studied in 30 patients undergoing ablation for AF: 16 patients in AF, 14 in sinus rhythm (SR), 18 remote robotic navigation (RRN) procedures. A SmartTouch contact force (CF) sensing catheter (Biosense Webster, USA) was used to collect CF data. All data were analysed using custom written scripts in the Matlab (MathWorks, USA) environment. CF variability (CFV: difference between 20Hz-sampled CF waveform mean peak and trough) increased with mean CF (Spearman's rho 0.6, p<0.005), and varied by location, being highest at the LA roof. Catheter drift correlated weakly with CF (Spearman's rho −0.05, p=0.005). CFV and drift were higher in SR than AF (p<0.001 for each). In AF there was less catheter drift for RRN than manual navigation points but the converse was true in SR (p<0.001 for both). CFV was higher with RRN (p<0.005). In 747 static 30s LA ablations, the influence of contact parameters on ablation efficacy was compared by multivariate analysis of impedance drop during ablation: a lesser drop suggesting reduced efficacy (Table). Greater CFV, locational drift, perpendicular contact, SR and RRN usage were associated with reduced efficacy (p<0.005 for each), even with ablation force time integral included in this analysis. Dependent Variable: Square root of percentage impedance drop Reference Location: Right WACA A positive β value for a co-factor means that if all the other co-factors are unchanged, the impedance drop will be higher as the co-factor increases (and vice versa) . Conclusions: Beyond ablation CF magnitude and duration, the quality of catheter contact also influences ablation efficacy. Clinical catheter contact is affected by multiple factors, including contact orientation, atrial rhythm and catheter navigation mode. Ablations should be performed in parallel contact with CFV ≤10g and catheter drift ≤3.5mm to maximize efficacy. | Multivariate analysis of factors affecting impedance drop during ablation | |:-------------------------------------------------------------------------:| ------------------------------------------ | | Co-factor | Unstandardized β (95% Confidence Interval) | p-value | | Ln(Force Time Integral) g.s | 0.78 (0.77 to 0.78) | <0.005 | | Remote Robotic Navigation | −0.08 (−0.1 to −0.07) | <0.005 | | Catheter drift >3.5mm | −0.22 (−0.24 to −0.2) | <0.005 | | Contact Force Variability (g) | −0.03 (−0.03 to −0.02) | <0.005 | | Perpendicular Contact Orientation | −0.03 (−0.04 to −0.02) | <0.005 | | Sinus Rhythm | −0.07 (−0.09 to 0.05) | <0.005 | | Left Atrial Body (non-WACA) | 0.1 (0.08 to 0.11) | <0.005 | | Left WACA | 0.06 (0.05 to 0.07) | <0.005 |

Randomized trial comparing robotic to manual ablation for atrial fibrillation

Catheter ablation of atrial fibrillation (AF) is a physically demanding procedure for the operator, involving radiation exposure, and has limited success rates. Remote robotic navigation (RRN) may offer benefit to the procedure, though only 1 previous small randomized trial has assessed this. This study aimed to investigate the impact of RRN on 1-year single-procedure success rates. RRN was compared to manual ablation in a randomized control trial setting by using an intention-to-treat analysis. A total of 157 patients underwent ablation (116/157 (74%) persistent AF; 67/116 (58%) of these long-standing persistent AF). There were no significant differences between the RRN and manual groups with respect to 1-year single-procedure success rates (19/78 (24%) and 26/78 (33%), respectively; P = .29), acute wide area circumferential ablation reconnection rates, complication rates, or procedure times. On multivariable analysis, fluoroscopy times were significantly shorter in the RRN group. The number of catheter displacements during ablation was lower in the RRN group, as was subjectively assessed operator fatigue. The crossover rate from RRN to manual ablation was 11/78 (14%), mainly secondary to technical problems with the RRN system. A learning curve was evident for RRN ablation: the fluoroscopy and procedure times were significantly lower after the first 10 cases in an operator's experience. This randomized trial showed no difference in the success rate for catheter ablation of AF between a RRN and manual approach. The results highlight the learning curve for RRN ablation and suggest that the use of this technology leads to an improvement in fluoroscopy times, catheter stability, and operator fatigue.

First in-human robotic rotor ablation for atrial fibrillation

Pulmonary vein isolation (PVI) is the cornerstone of most atrial fibrillation (AF) ablation procedures. Recent studies demonstrate that in AF, rapidly activating spiral-circuits called ‘rotors’ can be localized with computational-mapping during an electrophysiological study. Radiofrequency ablation at the rotor may result in AF termination. Remote robotic-navigation (RN) is designed to improve catheter stability and decrease radiation exposure. We report the first in-human rotor-mapping with a novel 64-electrode basket catheter (FIRMap®, …

Left atrial isthmus line ablation using a remote robotic navigation system: feasibility, efficacy and long-term outcome

Left atrial isthmus (LAI)-ablation in addition to circumferential pulmonary vein isolation (CPVI) may improve outcomes in select patients with atrial fibrillation (AF). However, bidirectional LAI-block is difficult to obtain. No systematic evaluation reporting on the feasibility and efficacy of LAI-ablation using a robotic navigation system (RNS) exists. In this pilot study, CPVI combined with LAI-ablation were performed using a RNS and 3D-mapping system in 42 patients with persistent (n = 24, 57.1 %) or longstanding persistent AF. Ablation was performed using either a 3.5 mm irrigated tip catheter (ITC) with 6 (group-A, n = 16; max. 40 W, contact force 10-40 g) or (after a steam pop occurred in one patient) with a 4 mm ITC with 12 irrigation holes (group-B, n = 26; max. 30 W, contact force 10-30 g). Epicardial ablation was performed manually whenever bidirectional LAI-block could not be obtained with a maximum of 20 endocardial RF-applications. LAI-conduction block was achieved in all patients using RNS; in six patients (14.3 %), additional epicardial ablation was required to achieve LAI-block. A steam pop occurred during LAI-ablation resulting in cardiac tamponade in one patient in group-A. After a median follow-up period of 21 months, arrhythmia recurrence was seen in in 23/42 patients (18 patients with AF and 5 patients with atrial tachycardia) and repeat procedure was performed in 12 (28.6 %) patients; recovered LAI-conduction was found in 5/12 (41.7 %) patients. The RNS-group was compared to a historical group of 20 patients with manual LAI-ablation. Using RNS, LAI-block was more often achieved (42 (100 %) vs 16 (80 %), p < 0.01) and epicardial ablation was required in a significantly smaller number of patients (6 (14.3) vs 10 (50 %), p < 0.01). LAI-ablation using RNS appears to be feasible in all patients. At repeat procedure, LAI-conduction can frequently occur; power and contact-force adaption appears to be mandatory to reduce the risk of complications. Using RNS, instead of a manual approach for LAI-line ablation may facilitate creation of a bidirectional LAI-block.

Auditory Feedback and Sensory Substitution During Teleoperated Navigation

Various modes of sensory feedback have the potential to improve robotic navigation performance. This paper proposes a novel way of using auditory feedback as a substitute for visual feedback to ensure that teleoperated robotic systems still function in real time under unfavorable communication conditions, such as with image losses, visual failures, or low-bandwidth communication links. The proposed theoretical frame consists of a translation model that links auditory and visual modalities with the help of ecological psychology. An experimental system is developed to test the feasibility of this conceptual model through psychoacoustic experiments with ten subjects that conduct real-time robotic navigation tasks. Assessment of this implementation provides convincing experimental evidence of the usefulness of auditory feedback as a complement to or substitute for visual display for remote robotic navigation. This is very beneficial when the network is congested or when the available bandwidth is low. This technology is also useful as a navigation aid for the visually impaired. However, an actual integrated system remains to be developed and evaluated.

Incidence and Long-Term Follow-Up of Silent Cerebral Lesions After Pulmonary Vein Isolation Using a Remote Robotic Navigation System as Compared With Manual Ablation

The incidence of silent cerebral lesions (SCL) after atrial fibrillation (AF) ablation is highly variable, depending on the technology used. Recently, an increased risk for SCL has been described for a novel, nonirrigated ablation tool using multielectrode phased radiofrequency (PVAC). The aim of this prospective study was to evaluate the incidence and long-term follow-up of SCL in patients undergoing robotically assisted pulmonary vein isolation (RA-PVI) as compared with manual PVI. Circumferential PVI using irrigated radiofrequency current was performed on 70 patients (41 patients with paroxysmal AF, 59%). Fifty patients underwent RA-PVI and 20 patients underwent a manual approach. Cerebral MRI was performed the day before and the day after the ablation procedure; follow-up MRI was performed on 9 of 12 (75%) patients after a follow-up period of 21 months. SCLs were found in 12 of 70 (17%) patients in this study; the incidence of SCLs was similar in patients undergoing RA-PVI as compared with manually ablated patients (n=9, 18% versus n=3, 15%; probability value=1.0). In 1 patient undergoing manual PVI (1%), an SCL with asymptomatic subarachnoid hemorrhage was detected; the bleeding completely resolved within 1 month. Transient ischemic attack occurred in 1 (1%) patient 2 days after manual PVI. After a median follow-up period of 21 months, no residual SCLs were detected. The incidence of SCL using the robotic navigation system was 18% in this study. Incidence and size of SCL appears to be similar after RA-PVI as compared with manual PVI. Repeat MRI showed no residual SCLs at long-term follow-up.

Development of an eye-tracking control system using AForge.NET framework

Assistive technology is taken one step ahead with the introduction of sophisticated eye-tracking and gaze-tracking techniques which track the movement of the eye and the gaze location to control various applications. This paper describes in detail the low-cost hardware development and the software architecture for a real-time eye-tracking based wireless control system using the open-source image processing framework of AForge.NET. The system developed has been tested in the field of remote robotic navigation, using the Lego NXT Mindstorm robot, and wireless home automation, using the X10 transmission protocol. The system designed uses a wireless camera to detect the eye movements and transmit control signals over a wireless channel. This provides a highly useful alternative control system for a person suffering from quadriplegia i.e. full body paralysis. Tests conducted to measure the processing time, system accuracy and error aid in evaluating the performance of the developed eye-tracking system.

Robot-Assisted Stenting of a High-Grade Anastomotic Pulmonary Artery Stenosis Following Single Lung Transplantation

To report robot-assisted stenting of a stenosis at the pulmonary artery anastomosis following lung transplantation, a rare complication that conveys poor prognosis even after surgical correction. The technique is illustrated in a 72-year-old man with end-stage lung disease who received a left single lung transplant. On postoperative day 54, he was evaluated for recurrent dyspnea on exertion that was due to a severe stenosis at the site of the pulmonary artery anastomosis. Balloon angioplasty was performed, and a 10-mm stent was deployed, with marked clinical improvement. Fourteen months later, he presented with recurrent symptoms due to in-stent restenosis. Multiple attempts at catheterization and balloon angioplasty of the stent failed. Due to the technical difficulty involved in maneuvering the balloon while maintaining stability, it was decided to repeat the angioplasty with the assistance of a Hansen Sensei remote robotic navigation system. The robotic arm markedly enhanced stability and facilitated successful navigation of the stented site. A 16-mm-diameter Wallstent was placed through the previously placed balloon-expandable stent and postdilated. A remote robotic catheter navigation system was able to assist stenting of an anastomotic pulmonary artery stenosis following failure of conventional interventional techniques.

Prevention of oesophageal injury during catheter ablation of atrial fibrillation: is monitoring of oesophageal temperature the solution?

This editorial refers to ‘Oesophageal temperature monitoring and incidence of oesophageal lesions after pulmonary vein isolation using a remote robotic navigation system’ by A. Rillig et al. , Europace 2010;12:655–61. Atrio-oesophageal fistula is among the most dangerous complications of interventional treatment of atrial fibrillation. The complication was first observed during intraoperative radiofrequency ablation of atrial fibrillation1 but subsequently also reported after catheter based radiofrequency ablation of atrial fibrillation.2 Atrio-oesophageal fistula is associated with high mortality3 even if the correct diagnosis is made relatively early. However, the diagnosis of the complication often is delayed because of the significant time delay of its occurrence after the ablation procedure (which mostly is 1–4 weeks) and unspecific initial symptoms.3,4 The mechanism most likely leading to atrio-oesophageal fistula after radiofrequency ablation of atrial fibrillation is the induction of thermal oesophageal injury during the ablation procedure; this pathophysiologic pathway could recently be observed in a patient who declined intervention after diagnosis of atrio-oesophageal fistula.4 The incidence of oesophageal injury after radiofrequency ablation of atrial fibrillation has been described between 5% and almost 50%5–7 depending on the radiofrequency power settings and ablation strategies. After the initial injury of the oesophagus, inflammation, and tissue necrosis promoted by the biological milieu in the oesophagus seem to pave the way for the occurrence of atrio-esophagel fistula. However, it is unclear which factors determine the progression of the frequently observed oesophageal lesion to the relatively rare but …

Oesophageal temperature monitoring and incidence of oesophageal lesions after pulmonary vein isolation using a remote robotic navigation system

Oesophageal lesions (EL), a potential complication after pulmonary vein isolation (PVI), have been described recently. A new remote robotic navigation system (RNS; Hansen Medical) provides enhanced catheter stability along with more effective lesion placement. The aim of this prospective study was to evaluate temperature monitoring and incidence of EL when using RNS with an irrigated tip radiofrequency catheter for PVI. Circumferential PVI using RNS was performed in 73 patients (pts) with paroxysmal (n = 46, 63%) and persistent atrial fibrillation. An oesophageal temperature probe was placed in 58 (79.5%) pts and was integrated in the 3D-map (NavX). Power was limited to 25 W at the posterior wall, and in the case of an increase in temperature power was limited to 20 W. Endoscopy was performed in 42 pts within 24 h after PVI. In 44 of 58 (75.9%) pts, a significant rise in temperature (>39 degrees C) was observed. In 6 of 42 (14.3%) pts, an EL was found during endoscopy. In patients with EL, the body mass index (BMI) was significantly lower than in pts without EL (24.1 +/- 2.0 vs. 29.0 +/- 5.8, P = 0.047). The BMI of all patients with EL was <26, whereas all patients without EL had a BMI above 26. The EL showed brisk healing after re-endoscopy within 2 weeks in all pts. In patients undergoing PVI using the RNS, the incidence of EL is 14.3% when using power settings comparable to settings used in manual ablation. Patients with lower BMI (<26) are at higher risk for EL.

Persistent iatrogenic atrial septal defect after a single-puncture, double-transseptal approach for pulmonary vein isolation using a remote robotic navigation system: results from a prospective study

Persistent iatrogenic atrial septal defect (iASD) after transseptal puncture for pulmonary vein isolation (PVI) has been described recently as a complication of PVI. No data exists evaluating systematically the incidence and clinical implications of iASDs after PVI using a remote robotic navigation system (RNS) with sheaths with a distinct larger outer diameter. In this prospective study, 40 patients with either paroxysmal (n = 22, 55%) or persistent symptomatic atrial fibrillation were treated with circumferential PVI using an RNS. In all patients, a single-puncture, double-transseptal approach was used to access the left atrium. Transoesophageal echocardiography was performed before and the day after PVI as well as after a 3 and 6 months follow-up (FU). The day after ablation an iASD was detected in 38 of 40 (95%) patients with a mean diameter of 3.45 +/- 1.5 mm. At 6-month FU, the iASDs were closed in 30 of 39 (78.9%) patients. During the 6-month FU period, no patient died or suffered from cerebral or cardiac embolism. After a single-puncture, double-transseptal approach for PVI using the RNS, iASDs show a high spontaneous closure rate of 78.9% after a 6-month FU period. Persistent iASDs following PVI with the RNS are not associated with an increased rate of paradoxical embolism or with relevant shunting.

Remote Robotic Navigation and Electroanatomical Mapping for Ablation of Atrial Fibrillation

Background— Radiofrequency current ablation of atrial fibrillation (AF) requires high technical skills to achieve optimal catheter stability and is associated with an individually high x-ray exposure to both the patient and the operator. To facilitate catheter navigation and to reduce the operator’s x-ray burden, remote navigation (RN) systems have been developed. Considerations for navigation of a novel remote robotic navigation system in pulmonary vein isolation (PVI) procedures are reported. Methods and Results— In 65 patients with drug-refractory AF (43 paroxysmal, 22 persistent), complete circumferential PVI was performed using RN in conjunction with different electroanatomic mapping systems. Acute complete PVI using exclusively RN was achieved in 95%. The procedure time was 195�40 minutes. The operator’s x-ray exposure time was reduced by 6�4 minutes (35%) using RN. In 7 of 14 patients with persistent AF, conversion to sinus rhythm was achieved by radiofrequency current ablation. During a median follow-up period of 239 days (range, 184 to 314 days), 47 of 65 patients (73%) remained free of any documented atrial tachyarrhythmia recurrences after a single procedure. The relative proportion of patients remaining free of AF was 76% and 68% for paroxysmal and persistent AF, respectively. Conclusions— PVI using the novel RN system can be performed safely and effectively. One third of the operator’s fluoroscopy exposure time might be saved using RN. However, the questions of whether the overall fluoroscopy exposure is reduced by RN and whether RN improves PVI procedures needs to be assessed during a comparative trial between man and machine.

AUDITORY DISPLAY WITH SENSORY SUBSTITUTION FOR INTERNET-BASED TELEOPERATION: A FEASIBILITY STUDY

A critical challenge in telerobotic system is data communication over networks without performance guarantee. This paper proposes a novel way of using auditory feedback as the sensory feedback to ensure that the teleoperated robotic system still functions in a real-time fashion under the unfavorable communication conditions, such as image losses, visual failures, and low-bandwidth communication links. The newly proposed method is tested through psychoacoustic experiments with 10 subjects conducting real-time robotic navigation tasks. The performance is analyzed according to an objective point of view (time to finish task, distance away to the target measurements), as well as subjective workload assessments for different sensory feedbacks. Moreover, the bandwidth consumed when auditory information is applied is considerably lower, compared with the visual information. Preliminary results demonstrate the feasibility of auditory display as a complement or substitute to visual display for remote robotic navigation.

Early Experience with Robotic Navigation for Catheter Ablation of Paroxysmal Atrial Fibrillation

Pulmonary venous antra isolation (PVAI) is the cornerstone of catheter ablation procedure for drug refractory paroxysmal atrial fibrillation (AF). However, the procedure is technically challenging. Robotic navigation has a potential to expedite and facilitate the procedure. A robotic catheter control system was used for remote navigation-supported PVAI in 22 patients (mean age = 55 +/- 9 years, 16 males, study group). An irrigated-tip catheter with estimate of catheter force on the tissue was used. This was compared in nonrandomized fashion with conventional hand-controlled catheter ablation in 16 patients (mean age = 55 +/- 9 years, 13 males, control group). The procedures were performed under guidance of Ensite NavX navigation system (St. Jude Medical, St. Paul, MN, USA) and intracardiac echocardiography. Robotic navigation was associated with significantly shorter overall duration of radiofrequency delivery (1,641 +/- 609 vs 2,188 +/- 865 seconds, P < 0.01), shorter total procedural time (207 +/- 29 vs 250 +/- 62 minutes, P = 0.007), fluoroscopy exposure (15 +/- 5 vs 27 +/- 9 minutes, P < 0.001), and lower radiation dose (1,119 +/- 596 vs 3,048 +/- 2,029 mGy/m(2), P < 0.001). No complication was observed in either the study or the control group. During the 5 +/- 1 months follow-up in the study group and 9 +/- 3 months in the control group, 91% and 81% of patients, respectively, were AF free. In our early clinical experience, PVAI using a remote robotic catheter navigation was effective, safe, and associated with shorter procedural and fluoroscopic times than conventional PVAI.

Remote Magnetic Versus Manual Catheter Navigation for Ablation of Supraventricular Tachycardias: A Randomized, Multicenter Trial

The potential benefits of remote robotic navigation for catheter ablation procedures have not been demonstrated in controlled clinical trials. The purpose of this study was to compare remote magnetic catheter navigation to manual navigation for the ablation of common supraventricular arrhythmias. Patients with supraventricular arrhythmias due to atrioventricular (AV) nodal reentry, accessory pathways, or undergoing AV junctional ablation for complete heart block were randomized in a 3:1 ratio between magnetic (Niobe system and Helios II catheter, Stereotaxis, Inc., St. Louis, MO) and manual navigation for radiofrequency ablation at 13 centers. The primary endpoint of the study was total fluoroscopic time. Fifty-six patients were randomized to magnetic navigation and 15 to manual navigation. AV nodal reentry was the most common arrhythmia in both groups. Total fluoroscopy time was reduced in the magnetic navigation group (median 17.8 minutes, interquartile (IQ) range 9.9,27.8 minutes) compared to manual navigation (27.1, IQ 19.0,48.0, P < 0.05). The acute success rates (91% for magnetic and 87% for manual navigation, P > 0.05) did not differ between groups. The number of lesions delivered was less for magnetic navigation (6, IQ 4,9 vs 10, IQ 7, 26, P < 0.05). Total procedure time (median 151, IQ 111, 221 minutes magnetic and 151, IQ 110, 221 minutes manual) and complication rates (5.4% patients magnetic and 6.7% patients manual) were similar between the groups (both P > 0.05). Remote magnetic catheter navigation reduces fluoroscopic time and radiofrequency lesion deliveries for the ablation of common supraventricular arrhythmias compared to manual catheter navigation.

View-Synchronized Robotic Image-Guided Therapy for Atrial Fibrillation Ablation

A robotic catheter navigation system has been developed that provides a significant degree of freedom of catheter movement. This study examines the feasibility of synchronizing this robotic navigation system with electroanatomic mapping and 3-dimensional computed tomography imaging to perform view-synchronized left atrial (LA) ablation. This study consisted of a porcine experimental validation phase (9 animals) and a clinical feasibility phase (9 atrial fibrillation patients). Preprocedural computed tomography images were reconstructed to provide 3-dimensional surface models of the LA pulmonary veins and aorta. Aortic electroanatomic mapping was performed manually, followed by registration with the corresponding computed tomography aorta image using custom software. The mapping catheter was remotely manipulated with the robotic navigation system within the registered computed tomography image of the LA pulmonary veins. The point-to-surface error between the LA electroanatomic mapping data and the computed tomography image was 2.1+/-0.7 and 1.6+/-0.1 mm in the preclinical and clinical studies, respectively. The catheter was remotely navigated into all pulmonary veins, the LA appendage, and circumferentially along the mitral valve annulus. In 7 of 9 animals, circumferential radiofrequency ablation lesions were applied periostially to ablate 11 pulmonary veins. In patients, all of the pulmonary veins were remotely electrically isolated in an extraostial fashion. Adjunctive ablation included superior vena cava isolation in 6 patients, cavotricuspid isthmus ablation in 5 patients, and ablation of sites of complex fractionated activity and atypical LA flutters in 3 patients. This study demonstrates the safety and feasibility of an emerging paradigm for atrial fibrillation ablation involving the confluence of 3 technologies: 3-dimensional imaging, electroanatomic mapping, and remote robotic navigation.