- Email: [email protected]
Catheter location trial: A prospective randomised comparison of Carto, NavX and conventional for catheter ablation
Poster 1 (CRYO) may offer this facility because of its inherent reversibility at low energy levels - a minimal chill to a target site demonstrates efficacy without permanent destruction. Successful application of this premise requires knowledge of energy levels that are physiologically effective but not injurious. Since effective CRYO typically requires application times of 2-5 mins and temperatures (temps) of ⱕ-70°C, we tested the effects of tip temps from -10°C to -70°C in steps of 10°C always at a duration of 30s to determine the suitability of such brief minimal chill temps for target site pre-testing. We hypothesized that we would observe a change from temporary to permanent effect at some point along the temp continuum. Method: A porcine thigh model was used in these tests, whereby thigh muscle was exposed, fascia removed and the surface continuously flushed with warmed (body temp) autologous blood. CRYOs were delivered with the probe tip oriented vertical to the tissue surface at a contact surface area of 8.5mm2 and pressure of 10g. Multiple non-overlapping CRYOs were made to each thigh. After treatment, each animal was survived for 24-48 hrs, whereupon 30ml of 2% triphenyltetrazonlium chloride was infused IV to enhance the visibility of necrotic tissue. The animal then was sacrificed and treated tissues excised and fixed in 10% formalin for later measurement of gross lesion depth and diameter. Results: Three to seven CRYOs (mean 4.6⫾1.4) were made at each temp for a total of 32 CRYOs in two animals. Depth was measured at the deepest extent. Lesions were found at all temps. Average lesion depth and diameter at each temp were (in mm): -10: 2.3 x 5.7, -20: 2.5 x 5.5, -30: 1.1 x 2.3 -40: 1.8 x 3.5, -50: 1.3 x 2.3, -60: 1.0 x 2.3, -70: 2.5 x 4.5. Conclusions: These results indicate that permanent tissue injury occurs at all temps employed and that energies suitable for pre-testing with cryothermy must be warmer than previously thought. P1-52
WITHDRAWN
P1-53 PORCINE PULMONARY VEIN ABLATION USING A NOVEL ROBOTIC CATHETER CONTROL SYSTEM AND REAL-TIME INTEGRATION OF CT IMAGING WITH ELECTROANATOMICAL MAPPING *Vivek Y. Reddy, MD, Zachary J. Malchano, BS, Suhny Abbarra, MD, Indranill Basu Ray, MD, *Dan Wallace, *Jessica Grossman, MD, Christopher Houghtaling, DVM, Christina D. McPherson and Jeremy N. Ruskin, MD. Massachusetts General Hospital, Boston, MA and Hansen Medical, Inc., CA. Background: By providing greater degrees of freedom, robotic catheter movement could increase the safety and efficacy of catheter ablation particularly if performed with CT/MR image integration. This report is the first experience with a robotic steerable guide catheter system (RSGC) used in tandem with electroanatomical mapping (EAM) and an integrated 3D CT dataset to perform LA mapping and PV ablation. Methods: Normal swine (n ⫽ 5) were pre-operatively imaged using a 64-slice CT scanner. These images were segmented and reconstructed to produce 3D surface models of the LA and aorta. Initially, the aorta underwent manual EAM mapping (CARTO), followed by registration with the corresponding 3D CT dataset using custom software. After transseptal puncture, a mapping catheter (Navistar) was placed within the RSGC to perform remote LA mapping within the registered 3D CT image. In 4/5 cases, circumferential ablation lesions were applied to the PV ostia using an 8mm-tip RFA catheter; a Lasso catheter was used in 2 cases. Results: Registration using aorta EAM data alone resulted in an LA point-to-surface error of 2.4⫾1.9mm; incorporation of LA EAM data further refined the registration accuracy to an error of 2.0⫾1.7mm. Using the registered 3D image to visualize the real-time catheter location (Figure: catheter noted at LSPV ostium), remote robotic navigation into all PVs, the LAA and MVA was possible. Robotic circumferential RFA of 5 PVs was successful (4-RSPV, 1-LSPV; 11.2⫾1.8 lesions/PV); when used, the Lasso catheter confirmed electrical isolation. No perforations were noted on postmortem exam.
S121 Conclusions: This preclinical study demonstrates the safety and feasibility of a novel paradigm for LA-PV mapping/ablation involving the confluence of 3 technologies: 3D imaging, EAM & robotic catheter control.
P1-54 FEASIBILITY OF REGISTRATION OF 3D LEFT ATRIAL IMAGES FROM COMPUTED TOMOGRAPHY WITH PROJECTION IMAGES FROM FLUOROSCOPY Jasbir Sra, MD, *Regis Vaillant, PhD, *Melissa Vass, BS, David Krum, MS and Masood Akhtar, MD. Aurora Sinai/St. Luke’s Medical Centers, University of Wisconsin Medical School-MCC, Milwaukee, WI, GE Healthcare, Buc, France and GE Healthcare, Waukesha, WI. Anatomical structures such as the left atrium and pulmonary veins (PV) are not normally delineated by fluoroscopy because there is no inherent contrast differentiation between them and the surrounding anatomy. Representation of these anatomical structures via a 3D model obtained from CT scanning, and subsequent projection of these images over a fluoroscopic system may help in navigation of mapping and ablation catheters to the appropriate sites during electrophysiologic (EP) procedures. Methods: In this feasibility study, 20 consecutive patients (13 male, 7 female, mean age 62 years) underwent contrast-enhanced, ECG-gated CT scanning (Figure-left panel). Left atrial volumes were segmented from reconstructed data at 75% of the R-R interval. During the EP procedure, digital record/cine sequences were obtained (Center panel). Using predetermined algorithms, we registered the 3D images of the left atrium with fluoroscopic projections of the same structures (Right panel). Registration was performed by superimposing the SVC and the CS from the CT model over the CS catheter seen on the digital cine image. Results: Registration was successfully accomplished in all 20 patients. The accuracy of the registered images was assessed using: 1) Recordings from a basket catheter placed sequentially in the superior veins and 2) Injection of contrast into the pulmonary veins to assess overlapping of the contrast filled PVs with the corresponding vessels on the registered images. Conclusions: Registration of 3D models of the left atrium and PVs with the fluoroscopic images of the same is feasible. This could enable appropriate navigation and localization of the mapping and ablation catheters.
P1-55 CATHETER LOCATION TRIAL: A PROSPECTIVE RANDOMISED COMPARISON OF CARTO, NAVX AND CONVENTIONAL FOR CATHETER ABLATION Stuart J. Harris, MRCP, Dhiraj Gupta, MD, Maysaa Alzetani, MRCP, Mark J. Earley, MRCP, Simon C. Sporton, MD, Anthony W. Nathan, MD, FRCP and Richard J. Schilling, MD. St. Bartholomew’s Hospital, London, United Kingdom.
S122 Introduction: The EnSite NavX (Endocardial Solutions, Inc. St Paul, Minnesota.) non-fluoroscopic mapping system has the potential to reduce X-ray exposure during electrophysiological procedures. This is the first prospective randomised controlled study to compare radiation exposure, safety and cost between conventional, electroanatomical (Carto) and high frequency electrical field (NavX) mapping techniques. Methods: All patients undergoing catheter ablation (except AV node and AF ablation) were randomised to a Carto, NavX or conventional mapping procedures. Immediate procedural success was defined using standard criteria (eg bi-directional block for typical atrial flutter, non inducibilty of AVNRT/AVRT etc). All patients were seen 6 weeks following the procedure and success defined as both freedom from symptoms and no documented recurrence of any arrhythmia other than ectopy. Procedure costs included diagnostic and ablation catheters, Carto reference patch and the complete NavX kit. All costs are the published UK list prices. Statistical comparison was made against conventional procedures. Results: Eighty-nine patients (54% men) aged 48⫾17 (mean⫾SD) were randomised. 5 patients were withdrawn as no arrhythmia could be induced. There were no significant differences between Carto and NavX in any variable. Conclusion: For all catheter ablation procedures, procedure duration and outcome are similar for Carto, Navx and conventional procedures. Both Carto and NavX are associated with reduced fluoroscopy time and radiation dose compared to conventional x-rays but at an increased cost. The costs of NavX are likely to reduce as we become more comfortable using fewer catheters for EP procedures.
P1-56 DIFFERENCES IN SUCCESS OF REPEAT ABLATION PROCEDURE FOR RECURRENT ATRIAL FIBRILLATION AFTER TWO DIFFERENT ABLATION STRATEGIES: RESULTS FROM A PROSPECTIVE RANDOMIZED STUDY COMPARING PULMONARY VEIN ISOLATION VERSUS CIRCUMFERENTIAL PULMONARY VEIN ABLATION Isabel Deisenhofer, MD, Martin R. Karch, MD, Ju¨rgen Schreieck, MD, Bernhard Zrenner, MD, Heidi Estner, MD, Etienne Luciani, MD and Claus Schmitt, MD. German Heart Center, Munich, Germany. Background: Both, the electric isolation of pulmonary veins (PVI) and the circumferential pulmonary vein ablation (CPVA) have emerged as a curative therapy for atrial fibrillation (AF). However, repeat ablations are necessary after either of the techniques in approximately 10-30% of the patients. We wanted to assess the clinical value of repeat ablation after PVI and CPVA. Methods and Results: One hundred patients (P, 58⫾9 years) with symptomatic AF were randomly assigned to undergo either PVI or CPVA. PVI was guided by circumferential mapping of the ostium of PV. During
Heart Rhythm, Vol 2, No 5, May Supplement 2005 CPVA, circular lesions were performed around the left and right PV in addition to a line from the left inferior circular line to the mitral annulus guided by electroanatomical mapping. If recurrent symptomatic AF occurred, a repeat ablation with the same approach as initially used was performed. In a 12 month follow-up period, repeat ablation was performed in 12/50P (24%) after PVI and 22/50P (44%) after CPVA (p⫽0.004). 11/12P in the PVI group were re-ablated for AF only, in 1P, AF and left atrial flutter (LAFL) had occurred. In the CPVA group, AF alone was targeted during re-ablation in 9P, AF in conjunction with LAFL in 8P and LAFL alone in 5P. After a repeat PVI, 10/12P (83%) were in stable sinus rhythm (SR), including the 1P with LAFL. After a second CPVA, 6/22 P (27%) were in stable SR: Of these 6P in SR, 3P had been re-ablated for AF alone and 3P for AF in conjunction with LAFL. The difference in success of repeat ablation in both groups was statistically significant (p⫽0.007). Conclusion: The success of repeat ablation using the same approach once again was significantly higher with the PVI approach compared to CPVA. One explanation might be the well-known observation that PV-LA conduction resumes after initially successful PVI with subsequent relapse of AF: relapse occurs because of re-conduction of PV. In CPVA, the high incidence of LAFL with or without concomitant AF might be a major cause for the disappointing long term results of repeat ablation. P1-57 INITIAL EXPERIENCE WITH A NOVEL TELEROBOTIC SYSTEM FOR TRANSVENOUS LEAD IMPLANT TECHNIQUE Emanuela Marcelli, PhD, Laura Cercenelli, PhD, Saverio Marini, MD and Gianni Plicchi, PhD. Biomedical Technology Unit, Surgery and Transplantation Dept., Bologna University, Bologna, Italy. Background: Interventional cardiac procedures are challenging and complex and may require extended fluoroscopic exposure, increasing radiation risk for the physician: each hour of fluoroscopic imaging is associated with a lifetime risk of developing a fatal malignancy of 0.1% and a risk of a genetic defect of 20 per 1 million births. Recent pacing techniques for Cardiac Resynchronization Therapy in heart failure patients need long procedural times for lead placement (mean fluoroscopy time 77⫾19 minutes). We report our initial experience with a telerobotic system which allows the physician to manipulate leads in the cardiovascular system from a remote x-ray shielded control room, thus reducing radiation exposure. The system consists of an electrically powered controller, a driving unit and a wireless user interface enabling a remote-control of advancement/ retraction and rotation of leads and stylets. Methods: In 3 anesthetized sheep the use of the telerobotic system for lead placement in the Right Atrium (RA), Right Ventricle Apex (RVA) and Coronary Sinus Ostium (CSO), was compared with the standard manual procedure. For each procedure implantation times were recorded. Results: All interventional procedures were performed successfully without complications. The use of the telerobotic system resulted in an increase of the implantation time compared with the manual procedure (RA: 18⫾6 vs 12⫾4 minutes, RVA: 16⫾7 vs 9⫾3 minutes, CSO: 57⫾15 vs 42⫾18 minutes) probably due to the system’s learning curve for physicians. Conclusions: The novel telerobotic system proved to be a feasible tool for remote lead and stylet control, removing physicians from the hazards of the x-ray field. A significant decrease of the implantation time may be achieved with increased experience with the telerobotic device.
WITHDRAWN
P1-53 PORCINE PULMONARY VEIN ABLATION USING A NOVEL ROBOTIC CATHETER CONTROL SYSTEM AND REAL-TIME INTEGRATION OF CT IMAGING WITH ELECTROANATOMICAL MAPPING *Vivek Y. Reddy, MD, Zachary J. Malchano, BS, Suhny Abbarra, MD, Indranill Basu Ray, MD, *Dan Wallace, *Jessica Grossman, MD, Christopher Houghtaling, DVM, Christina D. McPherson and Jeremy N. Ruskin, MD. Massachusetts General Hospital, Boston, MA and Hansen Medical, Inc., CA. Background: By providing greater degrees of freedom, robotic catheter movement could increase the safety and efficacy of catheter ablation particularly if performed with CT/MR image integration. This report is the first experience with a robotic steerable guide catheter system (RSGC) used in tandem with electroanatomical mapping (EAM) and an integrated 3D CT dataset to perform LA mapping and PV ablation. Methods: Normal swine (n ⫽ 5) were pre-operatively imaged using a 64-slice CT scanner. These images were segmented and reconstructed to produce 3D surface models of the LA and aorta. Initially, the aorta underwent manual EAM mapping (CARTO), followed by registration with the corresponding 3D CT dataset using custom software. After transseptal puncture, a mapping catheter (Navistar) was placed within the RSGC to perform remote LA mapping within the registered 3D CT image. In 4/5 cases, circumferential ablation lesions were applied to the PV ostia using an 8mm-tip RFA catheter; a Lasso catheter was used in 2 cases. Results: Registration using aorta EAM data alone resulted in an LA point-to-surface error of 2.4⫾1.9mm; incorporation of LA EAM data further refined the registration accuracy to an error of 2.0⫾1.7mm. Using the registered 3D image to visualize the real-time catheter location (Figure: catheter noted at LSPV ostium), remote robotic navigation into all PVs, the LAA and MVA was possible. Robotic circumferential RFA of 5 PVs was successful (4-RSPV, 1-LSPV; 11.2⫾1.8 lesions/PV); when used, the Lasso catheter confirmed electrical isolation. No perforations were noted on postmortem exam.
S121 Conclusions: This preclinical study demonstrates the safety and feasibility of a novel paradigm for LA-PV mapping/ablation involving the confluence of 3 technologies: 3D imaging, EAM & robotic catheter control.
P1-54 FEASIBILITY OF REGISTRATION OF 3D LEFT ATRIAL IMAGES FROM COMPUTED TOMOGRAPHY WITH PROJECTION IMAGES FROM FLUOROSCOPY Jasbir Sra, MD, *Regis Vaillant, PhD, *Melissa Vass, BS, David Krum, MS and Masood Akhtar, MD. Aurora Sinai/St. Luke’s Medical Centers, University of Wisconsin Medical School-MCC, Milwaukee, WI, GE Healthcare, Buc, France and GE Healthcare, Waukesha, WI. Anatomical structures such as the left atrium and pulmonary veins (PV) are not normally delineated by fluoroscopy because there is no inherent contrast differentiation between them and the surrounding anatomy. Representation of these anatomical structures via a 3D model obtained from CT scanning, and subsequent projection of these images over a fluoroscopic system may help in navigation of mapping and ablation catheters to the appropriate sites during electrophysiologic (EP) procedures. Methods: In this feasibility study, 20 consecutive patients (13 male, 7 female, mean age 62 years) underwent contrast-enhanced, ECG-gated CT scanning (Figure-left panel). Left atrial volumes were segmented from reconstructed data at 75% of the R-R interval. During the EP procedure, digital record/cine sequences were obtained (Center panel). Using predetermined algorithms, we registered the 3D images of the left atrium with fluoroscopic projections of the same structures (Right panel). Registration was performed by superimposing the SVC and the CS from the CT model over the CS catheter seen on the digital cine image. Results: Registration was successfully accomplished in all 20 patients. The accuracy of the registered images was assessed using: 1) Recordings from a basket catheter placed sequentially in the superior veins and 2) Injection of contrast into the pulmonary veins to assess overlapping of the contrast filled PVs with the corresponding vessels on the registered images. Conclusions: Registration of 3D models of the left atrium and PVs with the fluoroscopic images of the same is feasible. This could enable appropriate navigation and localization of the mapping and ablation catheters.
P1-55 CATHETER LOCATION TRIAL: A PROSPECTIVE RANDOMISED COMPARISON OF CARTO, NAVX AND CONVENTIONAL FOR CATHETER ABLATION Stuart J. Harris, MRCP, Dhiraj Gupta, MD, Maysaa Alzetani, MRCP, Mark J. Earley, MRCP, Simon C. Sporton, MD, Anthony W. Nathan, MD, FRCP and Richard J. Schilling, MD. St. Bartholomew’s Hospital, London, United Kingdom.
S122 Introduction: The EnSite NavX (Endocardial Solutions, Inc. St Paul, Minnesota.) non-fluoroscopic mapping system has the potential to reduce X-ray exposure during electrophysiological procedures. This is the first prospective randomised controlled study to compare radiation exposure, safety and cost between conventional, electroanatomical (Carto) and high frequency electrical field (NavX) mapping techniques. Methods: All patients undergoing catheter ablation (except AV node and AF ablation) were randomised to a Carto, NavX or conventional mapping procedures. Immediate procedural success was defined using standard criteria (eg bi-directional block for typical atrial flutter, non inducibilty of AVNRT/AVRT etc). All patients were seen 6 weeks following the procedure and success defined as both freedom from symptoms and no documented recurrence of any arrhythmia other than ectopy. Procedure costs included diagnostic and ablation catheters, Carto reference patch and the complete NavX kit. All costs are the published UK list prices. Statistical comparison was made against conventional procedures. Results: Eighty-nine patients (54% men) aged 48⫾17 (mean⫾SD) were randomised. 5 patients were withdrawn as no arrhythmia could be induced. There were no significant differences between Carto and NavX in any variable. Conclusion: For all catheter ablation procedures, procedure duration and outcome are similar for Carto, Navx and conventional procedures. Both Carto and NavX are associated with reduced fluoroscopy time and radiation dose compared to conventional x-rays but at an increased cost. The costs of NavX are likely to reduce as we become more comfortable using fewer catheters for EP procedures.
P1-56 DIFFERENCES IN SUCCESS OF REPEAT ABLATION PROCEDURE FOR RECURRENT ATRIAL FIBRILLATION AFTER TWO DIFFERENT ABLATION STRATEGIES: RESULTS FROM A PROSPECTIVE RANDOMIZED STUDY COMPARING PULMONARY VEIN ISOLATION VERSUS CIRCUMFERENTIAL PULMONARY VEIN ABLATION Isabel Deisenhofer, MD, Martin R. Karch, MD, Ju¨rgen Schreieck, MD, Bernhard Zrenner, MD, Heidi Estner, MD, Etienne Luciani, MD and Claus Schmitt, MD. German Heart Center, Munich, Germany. Background: Both, the electric isolation of pulmonary veins (PVI) and the circumferential pulmonary vein ablation (CPVA) have emerged as a curative therapy for atrial fibrillation (AF). However, repeat ablations are necessary after either of the techniques in approximately 10-30% of the patients. We wanted to assess the clinical value of repeat ablation after PVI and CPVA. Methods and Results: One hundred patients (P, 58⫾9 years) with symptomatic AF were randomly assigned to undergo either PVI or CPVA. PVI was guided by circumferential mapping of the ostium of PV. During
Heart Rhythm, Vol 2, No 5, May Supplement 2005 CPVA, circular lesions were performed around the left and right PV in addition to a line from the left inferior circular line to the mitral annulus guided by electroanatomical mapping. If recurrent symptomatic AF occurred, a repeat ablation with the same approach as initially used was performed. In a 12 month follow-up period, repeat ablation was performed in 12/50P (24%) after PVI and 22/50P (44%) after CPVA (p⫽0.004). 11/12P in the PVI group were re-ablated for AF only, in 1P, AF and left atrial flutter (LAFL) had occurred. In the CPVA group, AF alone was targeted during re-ablation in 9P, AF in conjunction with LAFL in 8P and LAFL alone in 5P. After a repeat PVI, 10/12P (83%) were in stable sinus rhythm (SR), including the 1P with LAFL. After a second CPVA, 6/22 P (27%) were in stable SR: Of these 6P in SR, 3P had been re-ablated for AF alone and 3P for AF in conjunction with LAFL. The difference in success of repeat ablation in both groups was statistically significant (p⫽0.007). Conclusion: The success of repeat ablation using the same approach once again was significantly higher with the PVI approach compared to CPVA. One explanation might be the well-known observation that PV-LA conduction resumes after initially successful PVI with subsequent relapse of AF: relapse occurs because of re-conduction of PV. In CPVA, the high incidence of LAFL with or without concomitant AF might be a major cause for the disappointing long term results of repeat ablation. P1-57 INITIAL EXPERIENCE WITH A NOVEL TELEROBOTIC SYSTEM FOR TRANSVENOUS LEAD IMPLANT TECHNIQUE Emanuela Marcelli, PhD, Laura Cercenelli, PhD, Saverio Marini, MD and Gianni Plicchi, PhD. Biomedical Technology Unit, Surgery and Transplantation Dept., Bologna University, Bologna, Italy. Background: Interventional cardiac procedures are challenging and complex and may require extended fluoroscopic exposure, increasing radiation risk for the physician: each hour of fluoroscopic imaging is associated with a lifetime risk of developing a fatal malignancy of 0.1% and a risk of a genetic defect of 20 per 1 million births. Recent pacing techniques for Cardiac Resynchronization Therapy in heart failure patients need long procedural times for lead placement (mean fluoroscopy time 77⫾19 minutes). We report our initial experience with a telerobotic system which allows the physician to manipulate leads in the cardiovascular system from a remote x-ray shielded control room, thus reducing radiation exposure. The system consists of an electrically powered controller, a driving unit and a wireless user interface enabling a remote-control of advancement/ retraction and rotation of leads and stylets. Methods: In 3 anesthetized sheep the use of the telerobotic system for lead placement in the Right Atrium (RA), Right Ventricle Apex (RVA) and Coronary Sinus Ostium (CSO), was compared with the standard manual procedure. For each procedure implantation times were recorded. Results: All interventional procedures were performed successfully without complications. The use of the telerobotic system resulted in an increase of the implantation time compared with the manual procedure (RA: 18⫾6 vs 12⫾4 minutes, RVA: 16⫾7 vs 9⫾3 minutes, CSO: 57⫾15 vs 42⫾18 minutes) probably due to the system’s learning curve for physicians. Conclusions: The novel telerobotic system proved to be a feasible tool for remote lead and stylet control, removing physicians from the hazards of the x-ray field. A significant decrease of the implantation time may be achieved with increased experience with the telerobotic device.