P6-84

Poster 6 This most likely accounted for the clinical ECG and IC signals discrepancies found between the systems. Conclusion: A portable wireless multi-channel EP Rec system can be used for ECG and IC signal transmission/recording. This new system provides improved signal quality and fidelity. This may allow for more accurate signal recognition during mapping which may favorably impact on the outcome of certain ablation procedures. Current system limitations include number of IC channels and lack of tools for signal analysis. P6-83 MULTIFOCAL ARRHYTHMOGENICITY OF THE CORONARY SINUS IN CHRONIC ATRIAL FIBRILLATION Me´le`ze Hocini, MD, Yoshihide Takahashi, MD, Prashanthan Sanders, MBBS, PhD, Pierre Jaı¨s, MD, PhD, Mark D. O’Neill, MBBS, PhD, Anders Jonsson, MD, Martin Rotter, MD, Thomas Rostock, MD, Fre´de´ric Sacher, MD, Li-Fern Hsu, MD, MBBS, Pierre Bordachar, MD, Julien Laborderie, MD, Michel Haı¨ssaguerre, MD and Jacques Cle´menty, MD. Hoˆpital Cardiologique du Haut Le´ve`que, Bordeaux-Pessac, France. The coronary sinus (CS) and its connections to the right and left atria (LA) are important in perpetuating chronic atrial fibrillation (AF) in humans. We investigated the safety and efficacy of disconnecting the CS and the impact of such ablation during chronic AF. Methods: 99 patients with AF lasting for 17⫾25 months (age 53⫾ 9yrs; 54 structural heart disease) underwent catheter ablation of chronic AF involving pulmonary veins, superior vena cava and CS, atrial tissue displaying fractionated electrograms, rapid and/or heterogeneous activity and linear lesions at the LA roof and/or mitral isthmus. The role of the CS was evaluated i) during CS ablation in AF based on the impact on AF cycle length (AFCL) ii) as the site of origin of atrial tachycardia (AT). Isolation of the CS was commenced along the endocardial aspect (with the catheter looped along the inferior LA to be positioned parallel to the CS catheter) and completed within the vessel in pts with persistent CS potentials. AFCL was measured in the CS and in the LA appendage. A cooled tip ablation catheter was utilized with a power limit of 25 to 30W within the CS. Results: Endocardial ablation along the mitral annulus prolonged the CL of CS electrograms by 19⫾24 msec and totally eliminated CS potentials in 4 patients. The impact on global AFCL was as follows i) endocardial ablation increased AFCL by ⱖ 5msec in 47% of patients ii) epicardial ablation prolonged AFCL in 43% of patients. Furthermore, the CS was the site of conversion to AT or sinus rhythm in 21 patients; along the endocardial aspect in 9, within the proximal CS in 5, distal CS in 4, around the CS ostium in 2 and multifocal in one. 3 patients had persistent arrhythmia discharges within the isolated CS. Lastly, the CS was the site of origin of AT in 15 patients. No complications occurred in this series. Conclusions: The coronary sinus is a major structure perpetuating chronic atrial fibrillation. Arrhythmias may originate along the entire length of the coronary sinus and can be safely eliminated. The full impact of ablation during atrial fibrillation may require endocardial, epicardial or both sites of ablation. P6-84 LANDMARK REGISTRATION VERSUS SURFACE REGISTRATION OF CT WITH REAL TIME MAP USING CARTO-MERGE IN ATRIAL FIBRILLATION Neil R. Brysiewicz, BS, Joseph G. Akar, MD, PhD, Peter A. Santucci, MD, Niraj Varma, MD, FRCP, Ray Helms, MD, Mitchell Mark, DO, Magdi Saba, MD, Michael Porter, MD and David J. Wilber, MD. Loyola University Medical Center, Maywood, IL. A simplified Affine registration (reg) is used to merge a CT scan with a real time map in CARTO-Merge ( Biosense-Webster, Inc.). This process is driven by a set of landmarks. If choosing three CARTO-Landmark points, the reg algorithm uses those points to align the CT and map. If the CT is

S329 moved into position using manual translation and merged using surface reg, the algorithm uses all map points as landmarks and an optimization algorithm chooses the most logical landmarks on the CT to use in the reg algorithm. Methods: CT scans were merged to CARTO maps for 51 patients with A Fib. Surface reg was used for 26 pts (mean age 56 ⫾ 9yrs, 19M, 7F) and landmark reg was used for 25 pts (mean age 56 ⫾ 11yrs, 19M, 6F). The match statistics reports the avg distance of the landmarks on the map to the landmarks on the CT scan. The time between the first landmark point and the first ablation was used to calculate the time taken to merge. A two tailed unequal variance T-test was used to calculate the P values. Surface reg was accurate within 2.64mm ⫾ 0.91, while landmark reg was accurate within 11.05mm ⫾ 3.68 (P ⬍ 0.001). The time it takes to mark three accurate landmarks is 11.47min ⫾ 9.38 and it takes 6.17min ⫾ 5.59 (P ⫽ 0.016). Conclusion: Surface registration takes less time and is more accurate than landmark registration.

Landmark Registration Surface Registration

Time Taken to Merge

Distance between CT and Map

P

11.47min ⫾ 9.38

11.05mm ⫾ 3.68

0.016

6.17min ⫾ 5.59

2.64mm ⫾ 0.91

⬍0.001

P6-85 THE REGIONAL DISTRIBUTION AND CORRELATION BETWEEN DIFFERENT ATRIAL ELECTROGRAM CHARACTERISTICS AND DOMINANT FREQUENCY DURING ATRIAL FIBRILLATION Wanwarang Wongcharoen, MD, Ching-Tai Tai, MD, YennJiang Lin, MD, Shih-Lin Chang, MD, Li-Wei Lo, MD, ShengHsiung Chang, MD and Shih-Ann Chen, MD. Taipei Veterans General Hospital, Taipei, Taiwan Republic of China. Background: Complex fractionated atrial electrograms (CFAE) and the sites of high-frequency activity during atrial fibrillation (AF) have been proposed to be the target sites to eliminate AF. However, the regional distribution of CFAE and the relationship between atrial electrogram (Eg) characteristics and frequency activity during AF are unknown. Methods: This study included 11 patients with paroxysmal and 5 patients with persistent AF ( age 43⫾12 yr, male⫽ 13). Frequency analysis was