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High-density mapping for identifying sources during ongoing atrial fibrillation
S280 Background: Cardiac 3D imaging can be performed before an EP procedure and integrated with real-time electroanatomical mapping (EAM) to guide cardiac mapping. However, because the MRI in this image integration paradigm is acquired pre-procedure, the cardiac anatomy during the procedure can change due to biological factors. Interventional MR imaging (iMRI) could combine real-time EAM with real-time MR imaging, thereby providing real-time anatomical information to guide catheter mapping. Methods & Results: Imaging and tracking data were acquired using a 1.5 T GE Signal CVi MRI, and electrogram information with a modified CardioLab 7000 EP recording system. Both in vitro and in vivo experiments were conducted to evaluate catheter tracking and EAM in the iMRI environment. During in vitro stuides, MR angiography (MRA) was completed on a fluid filled phantom of the aorta and left heart. These images were then semi-automatically segmented (CardEP, GE Medical) and 3D reconstructions prepared. An MR-compatible mapping catheter (see Figure; St. Jude Medical) with 3 MR tracking coils was advanced into the lumen of the phantom. During the in vivo porcine experiments, contrastenhanced MRA was completed. Following reconstruction of the imaging data, the deflectable catheter was manipulated under real-time iMRI image guidance. Real-time catheter position was updated continuously at 30 frames per second, and continuous MR imaging during tracking provided real-time update of the imaging planes. Using this methodology, mapping of the cardiac chambers to display the electrical information on the MR 3D anatomy was possible. Conclusions: This feasibility study demonstrates real-time tracking of an MR-compatible catheter to perform electroanatomical mapping within the MR environment. With further refinements, iMRI may be a clinicallyfeasible navigation paradigm.
P5-82 HIGH-DENSITY MAPPING FOR IDENTIFYING SOURCES DURING ONGOING ATRIAL FIBRILLATION Yoshihide Takahashi, MD, Me´le`ze Hocini, MD, *Prashanthan Sanders, MBBS, Martin Rotter, MD, *Pierre Jaı¨s, MD, PhD, Thomas Rostock, MD, Fre´de´ric Sacher, MD, Chrishan J. Nalliah, BSc, Ste´phane Garrigue, MD, PhD, Jacques Cle´menty, MD and *Michel Haı¨ssaguerre, MD. Hoˆpital Cardiologique du Haut Le´ve`que, Bordeaux, France. The feasibility of mapping atrial driving sources during ongoing atrial fibrillation (AF) has not been reported. We used a 5-spine 20-pole catheter for high-density mapping during ongoing AF to investigate the mechanism of AF maintenance. Methods: 12 patients (54 years, 1 female, 9 paroxysmal AF, 3 persistent or chronic AF) were studied. Mapping catheter which has 5 spines and 4 electrodes in each spine, was inserted into left atrium transseptally. Mapping was performed for ⬎30 sec at each site during sustained AF prior to catheter ablation. Results: Mapping was performed during spontaneous AF in 9 patients and induced AF in 3 patients, and 72 sites were mapped. Beat-to-beat change in the pattern of propagation (non-synchronous), and one specific propagation pattern in consecutive ⱖ3 beats (synchronous) were observed in 56 (78%) and 16 (22%) sites, respectively. In 9 sites (13%, 7 patients), sources
Heart Rhythm, Vol 2, No 5, May Supplement 2005 were observed, which was identified by centrifugal activation sequence (center to peripheral bipoles) and a gradient of cycle length (proximal bipole: 149⫾49 ms, distal bipole: 178⫾31 ms, p ⬍0.02). Firing of sources was episodic (duration: 500 - 2300 msec). The mechanism of firing was possibly reentry in 3 sites based on continuous activity covering the whole cycle length and, other 6 are considered triggered activity or abnormal automaticity because of significant gradient of cycle length between surrounding bipoles. Conclusions: This preliminary study demonstrates the feasibility of mapping atrial driving sources during ongoing AF with use of a high-density multi-spine catheter. This may help to understand the mechanism of AF maintenance and improve the efficacy of AF ablation. P5-83 LEFT VENTRICULAR LEAD PLACEMENT WITHIN A CORONARY SINUS SIDE BRANCH IS FEASIBLE USING REMOTE MAGNETIC NAVIGATION OF A GUIDEWIRE Maximo J. Rivero-Ayerza, MD, Andrew S. Thornton, MD, Marcoen Scholten, MD, Joris Mekel, MD, Jan Res, MD, Dominic Theuns, MD and Luc Jordaens, MD, PhD. Erasmus Medical Center, Rotterdam, Netherlands. Background: A novel magnetic navigation system has been designed with the purpose of allowing remote guidance of catheters and guide-wires, with the aim of reaching areas or accessing vessels otherwise difficult to get to by conventional means. Objective: This study was conducted with the purpose of: (1) evaluating the feasibility of deploying a LV pacing lead into a desired CS side branch using a magnetically guided wire, (2) testing the feasibility of performing the procedure without the need for a guiding sheath inserted in the CS. Methods: We included 5 consecutive patients (pts), with an indication for cardiac resynchronization therapy. In patients 1 to 3 the pre-established strategy was to perform the procedure using a guiding sheath to cannulate the CS os. In patients 4 and 5 the decision was to perform the entire procedure without the use of a CS sheath. In these cases a CS image obtained during the late phase of a previous coronary angiography was used as an anatomic guide to navigate and select the target branch. In these last pts the wire was advanced manually while the external magnets oriented it towards the CS os. Once in the CS (in all 5 pts) “vector based” navigation was used to guide the wire to the desired side branch. Afterwards an over the wire LV pacing lead was introduced. Results: In all 5 pts the target postero-lateral vessel could be successfully engaged by the magnetically guided wire. In 4 pts the LV lead was lodged in the target vessel. Due to instability, the LV lead was repositioned in an anterolateral side branch in 1 pt. LV lead properties were: mean sensing amplitude of 18⫾7 mV, mean pacing threshold of 2.1⫾1 V and mean impedance of 905⫾103 ohms. Procedure and radioscopy times were 197⫾60 min and 30⫾8 min respectively. In one patient phrenic-nerve stimulation threshold was 9 V and one required re-intervention due to late LV lead displacement. No major complications were observed. Conclusion: Left ventricular lead implantation can be successfully performed using a remote-magnetically steered guide-wire to engage the desired CS side branch. This procedure could be performed without the need of a CS guiding sheath. P5-84 PROSPECTIVE EVALUATION OF LEFT VENTRICULAR LEAD PLACEMENT WITHOUT A CORONARY SINUS GUIDE SHEATH Adam S. Helms, BS, *James P. Hummel, MD, *J. Michael Mangrum, MD, *John P. Dimarco, MD, PhD, *J. Paul Mounsey, MD, PhD and *John D. Ferguson, MD, MBBS. University of Virginia, Charlottesville, VA. Current techniques for implantation of left ventricular pacing leads via the coronary sinus (CS) employ a pre-shaped guide sheath. We have prospec-
P5-82 HIGH-DENSITY MAPPING FOR IDENTIFYING SOURCES DURING ONGOING ATRIAL FIBRILLATION Yoshihide Takahashi, MD, Me´le`ze Hocini, MD, *Prashanthan Sanders, MBBS, Martin Rotter, MD, *Pierre Jaı¨s, MD, PhD, Thomas Rostock, MD, Fre´de´ric Sacher, MD, Chrishan J. Nalliah, BSc, Ste´phane Garrigue, MD, PhD, Jacques Cle´menty, MD and *Michel Haı¨ssaguerre, MD. Hoˆpital Cardiologique du Haut Le´ve`que, Bordeaux, France. The feasibility of mapping atrial driving sources during ongoing atrial fibrillation (AF) has not been reported. We used a 5-spine 20-pole catheter for high-density mapping during ongoing AF to investigate the mechanism of AF maintenance. Methods: 12 patients (54 years, 1 female, 9 paroxysmal AF, 3 persistent or chronic AF) were studied. Mapping catheter which has 5 spines and 4 electrodes in each spine, was inserted into left atrium transseptally. Mapping was performed for ⬎30 sec at each site during sustained AF prior to catheter ablation. Results: Mapping was performed during spontaneous AF in 9 patients and induced AF in 3 patients, and 72 sites were mapped. Beat-to-beat change in the pattern of propagation (non-synchronous), and one specific propagation pattern in consecutive ⱖ3 beats (synchronous) were observed in 56 (78%) and 16 (22%) sites, respectively. In 9 sites (13%, 7 patients), sources
Heart Rhythm, Vol 2, No 5, May Supplement 2005 were observed, which was identified by centrifugal activation sequence (center to peripheral bipoles) and a gradient of cycle length (proximal bipole: 149⫾49 ms, distal bipole: 178⫾31 ms, p ⬍0.02). Firing of sources was episodic (duration: 500 - 2300 msec). The mechanism of firing was possibly reentry in 3 sites based on continuous activity covering the whole cycle length and, other 6 are considered triggered activity or abnormal automaticity because of significant gradient of cycle length between surrounding bipoles. Conclusions: This preliminary study demonstrates the feasibility of mapping atrial driving sources during ongoing AF with use of a high-density multi-spine catheter. This may help to understand the mechanism of AF maintenance and improve the efficacy of AF ablation. P5-83 LEFT VENTRICULAR LEAD PLACEMENT WITHIN A CORONARY SINUS SIDE BRANCH IS FEASIBLE USING REMOTE MAGNETIC NAVIGATION OF A GUIDEWIRE Maximo J. Rivero-Ayerza, MD, Andrew S. Thornton, MD, Marcoen Scholten, MD, Joris Mekel, MD, Jan Res, MD, Dominic Theuns, MD and Luc Jordaens, MD, PhD. Erasmus Medical Center, Rotterdam, Netherlands. Background: A novel magnetic navigation system has been designed with the purpose of allowing remote guidance of catheters and guide-wires, with the aim of reaching areas or accessing vessels otherwise difficult to get to by conventional means. Objective: This study was conducted with the purpose of: (1) evaluating the feasibility of deploying a LV pacing lead into a desired CS side branch using a magnetically guided wire, (2) testing the feasibility of performing the procedure without the need for a guiding sheath inserted in the CS. Methods: We included 5 consecutive patients (pts), with an indication for cardiac resynchronization therapy. In patients 1 to 3 the pre-established strategy was to perform the procedure using a guiding sheath to cannulate the CS os. In patients 4 and 5 the decision was to perform the entire procedure without the use of a CS sheath. In these cases a CS image obtained during the late phase of a previous coronary angiography was used as an anatomic guide to navigate and select the target branch. In these last pts the wire was advanced manually while the external magnets oriented it towards the CS os. Once in the CS (in all 5 pts) “vector based” navigation was used to guide the wire to the desired side branch. Afterwards an over the wire LV pacing lead was introduced. Results: In all 5 pts the target postero-lateral vessel could be successfully engaged by the magnetically guided wire. In 4 pts the LV lead was lodged in the target vessel. Due to instability, the LV lead was repositioned in an anterolateral side branch in 1 pt. LV lead properties were: mean sensing amplitude of 18⫾7 mV, mean pacing threshold of 2.1⫾1 V and mean impedance of 905⫾103 ohms. Procedure and radioscopy times were 197⫾60 min and 30⫾8 min respectively. In one patient phrenic-nerve stimulation threshold was 9 V and one required re-intervention due to late LV lead displacement. No major complications were observed. Conclusion: Left ventricular lead implantation can be successfully performed using a remote-magnetically steered guide-wire to engage the desired CS side branch. This procedure could be performed without the need of a CS guiding sheath. P5-84 PROSPECTIVE EVALUATION OF LEFT VENTRICULAR LEAD PLACEMENT WITHOUT A CORONARY SINUS GUIDE SHEATH Adam S. Helms, BS, *James P. Hummel, MD, *J. Michael Mangrum, MD, *John P. Dimarco, MD, PhD, *J. Paul Mounsey, MD, PhD and *John D. Ferguson, MD, MBBS. University of Virginia, Charlottesville, VA. Current techniques for implantation of left ventricular pacing leads via the coronary sinus (CS) employ a pre-shaped guide sheath. We have prospec-