Analysis of catheter contact force during atrial fibrillation ablation using the robotic navigation system: results from a randomized study.

PURPOSE: Contact with cardiac tissue is an important determinant of lesion efficacy during atrial fibrillation (AF) ablation. The Sensei X™ robotic navigation system (RNS) (Hansen Medical, Mountain View, CA, USA) has been validated for contact force (CF) sensing expressed in grams (g). The Thermocool® SmartTouch™ catheter enables the measurement of catheter tip CF and direction inside the heart. We aimed to investigate the catheter CF with and without RNS during pulmonary vein isolation (PVI) procedures. METHODS: Eighty patients with symptomatic AF (56 males, age 63 ± 18) were enrolled in this study. Fifty-seven patients had paroxysmal AF and 23 early persistent AF. All procedures were performed with the Thermocool® SmartTouch™ ablation catheter. Forty patients were randomized to perform PVI with the Sensei X™ RNS (group 1), while in the other 40 patients (group 2), PVI was performed without the RNS. RESULTS: AF ablation was performed successfully in all patients without complications, while contact force was kept in the established 10-40 g range. A significantly higher CF was documented on the PVs in group 1 compared to group 2. The 1-year freedom from AF recurrence was higher in group 1 compared to group 2 (90 vs. 65 %, p = 0.04). Moreover, a significant reduction of fluoroscopy time was noted in the RNS group (13 ± 10 vs. 20 ± 10 min, respectively, p = 0.05). CONCLUSIONS: The Sensei X™ RNS permits a significantly higher CF during transcatheter AF ablation with a low rate of AF recurrence at clinical follow-up.

Simultaneous assessment of contact pressure and local electrical coupling index using robotic navigation.

PURPOSE: Contact with cardiac tissue is a determinant of lesion efficacy during atrial fibrillation (AF) ablation. The Sensei®X Robotic Catheter System (Hansen Medical, CA) has been validated for contact force sensing. The electrical coupling index (ECI) from the EnSite Contact™ system (St. Jude Medical, MN) has been validated as an indicator of tissue contact. We aimed at analyzing ECI behavior during radiofrequency (RF) pulses maintaining a stable contact through the robotic navigation contact system. METHODS: In 15 patients (age, 59 ± 12) undergoing AF ablation, pulmonary vein (PV) isolation was guided by the Sensei®X System, employing the Contact™ catheter. RESULTS: During the procedure, we assessed ECI changes associated with adequate contact based on the IntelliSense® force-sensing technology (Hansen Medical, CA. Baseline contact (27 ± 8 g/cm(2)) ECI value was 99 ± 13, whereas ECI values in a noncontact site (0 g/cm(2)) and in a light contact site (1-10 g/cm(2)) were respectively 66 ± 12 and 77 ± 10 (p < 0.0001). Baseline contact ECI values were not different depending on AF presentation (paroxysmal AF, 98 ± 9; persistent AF, 100 ± 9) or on cardiac rhythm (sinus rhythm, 97 ± 7; AF,101 ± 10). In all PVs, ECI was significantly reduced during and after ablation (ECI during RF, 56 ± 15; ECI after RF, 72 ± 16; p < 0.001). A mean reduction of 32.2% during RF delivery and 25.4% immediately after RF discontinuation compared with baseline ECI was observed. CONCLUSIONS: Successful PV isolation is associated with a significant decrease in ECI of at least 20 %. This may be used as a surrogate marker of effective lesion in AF ablation.

Worldwide experience with the robotic navigation system in catheter ablation of atrial fibrillation: methodology, efficacy and safety.

INTRODUCTION: The Hansen Robotic system has been utilized in ablation procedures for atrial fibrillation (AF). However, because of the lack of tactile feedback and the rigidity of the robotic sheath, this approach could result in higher risk of complications. This worldwide survey reports a multicenter experience on the methodology, efficacy, and safety of the Hansen system in AF ablations. METHODS AND RESULTS: A questionnaire addressing questions on patient's demographics, procedural parameters, ablation success rate and safety information was sent to all centers where more than 50 robotic AF ablation cases have been performed. From June 2007 to December 2009, 1,728 procedures were performed at 12 centers utilizing the Hansen robotic navigation technology. The overall complication rate was 4.7% and the success rate was 67.1% after 18 ± 4 months of follow-up. In 5 low volume centers there appeared to be a learning curve of about 50 cases (complication rate 11.2% for the first 50 cases vs 3.7% for the 51-100 cases; P = 0.044) and a trend showing a decrease of complication rate with increasing case volume. However, in the remaining 7 centers no learning curve was present and the complication rate was stable over time (3.7% for the first 50 cases vs 3.6% for the 51st case thereafter; P = 0.942). CONCLUSION: The Hansen robotic system can be used for AF ablation safely. In low volume centers, there appeared to be a learning curve of the first 50 cases after which the complication rate decreased. With a higher case volume, the success rate increased.

Ablation of atrial fibrillation utilizing robotic catheter navigation in comparison to manual navigation and ablation: single-center experience.

BACKGROUND: Robotic catheter navigation and ablation either with magnetic catheter driving or with electromechanical guidance have emerged in the recent years for the treatment of atrial fibrillation. OBJECTIVE: The aim of this study was to compare our center's experience of atrial fibrillation ablation using the Hansen Robotic Medical System with our current manual ablation technique in terms of acute and chronic success, as well as procedure time and radiation exposure to both the patient and the operator. METHODS: A total of 390 consecutive patients with symptomatic and drug-resistant atrial fibrillation (289 males, 62 +/- 11 years) were prospectively enrolled in the study. All patients underwent the procedure either with conventional manual ablation (group 1, n = 197) or with the robotic navigation system (RNS) (group 2, n = 193). RESULTS: The success rate for RNS was 85% (164 patients), while for manual ablation it was 81% (159 patients) (p = 0.264) at 14.1 +/- 1.3 months with AADs previously ineffective. Fluoroscopy time was significantly lower for RNS (48.9 +/- 24.6 minutes for RNS vs. 58.4 +/- 20.1 minutes for manual ablation, P < 0.001). Mean fluoroscopy time was statistically reduced after 50 procedures (61.8 +/- 23.2 minutes for first 50 cases vs. 44.5 +/- 23.6 minutes for subsequent procedures, P < 0.0001). CONCLUSION: Robotic navigation and ablation of atrial fibrillation is safe and effective. Fluoroscopy time decreases with experience.

Atrial fibrillation ablation using a robotic catheter remote control system: initial human experience and long-term follow-up results.

OBJECTIVES: We present the initial clinical human experience with the use of a robotic remote navigation system (Hansen Medical, Mountain View, California), to perform left and right atrial mapping and radiofrequency ablation of atrial fibrillation (AF) and atrial flutter (AFL). BACKGROUND: Catheter ablation is an established curative modality for various arrhythmias. A robotic steerable sheath system (SSS) (Hansen Medical) allows better catheter stability and greater degrees of freedom of catheter movement. METHODS: A total of 40 patients (mean age 57 years) with antiarrhythmic drug (AAD)-refractory AF (23 had also concomitant documented typical AFL) were studied. Three-dimensional reconstruction of the corresponding atrial chamber anatomy was performed with the CARTO electroanatomic mapping system (Biosense Webster, Diamond Bar, California or the EnSite NavX system (St. Jude Medical, Minneapolis, Minnesota) in combination with the Artisan catheter (Hansen Medical). In patients undergoing AF ablation, 2 transseptal punctures were performed under intracardiac ultrasound (ICE) guidance, with one of the punctures being performed using SSS. Pulmonary vein antrum isolation was performed with a 3.5-mm thermocool catheter manipulated with the use of the SSS and was verified by circular mapping. Patients were followed clinically for recurrence of arrhythmia with an event transmitter and ambulatory holter monitoring. Clinical recurrence of AF/AFL was defined as AF/AFL episodes >1 min in duration. RESULTS: Pulmonary vein antrum isolation was performed in 40 patients, including 23 with concomitant typical AFL ablation. All pulmonary veins, including the superior vena cava, were successfully isolated. In 23 of 40 patients, cavotricuspid ablation was also performed with bidirectional block obtained. At 1-year follow-up, 34 patients (86%) and 5 patients were free from atrial arrhythmia off AADs and on AADs, respectively. CONCLUSIONS: This preliminary human experience suggests that mapping and ablation of AFL and AF using this novel robotic catheter with remote control system is feasible with similar results to conventional approach.