P3-66

Poster 3 P3-66 CHARACTERISTICS OF PAINFUL LESIONS DURING RADIOFREQUENCY ABLATION OF PULMONARY VEINS Jamshid Alaeddini, MD, Mark A. Wood, MD, Benjamin P. Lee, MD and Kenneth A. Ellenbogen, MD. Medical College of Virginia, Richmond, VA. Background: Radiofrequency (RF) ablation near or around the pulmonary veins (PV) may be associated with pain at specific sites during lesion delivery. However, the incidence, location, and temperature characteristics of RF lesions producing pain with an 8 mm catheter have not been prospectively studied. Methods: We studied 46 (30 men, age 55⫾10 years) patients with AF who underwent RF ablation of PVs between January 2005 and October 2005. Lesions were placed circumferentially in the antrum of each PV using an 8F, 8 mm BiosenseTm ablation catheter. An electroanatomic map was used to document the location of all lesions. Lesions producing pain were marked with a different color on the map and the time, PV location and maximum temperature of these lesions were recorded. Results: A total of 1402 (33⫾12) RF lesions were delivered to 187 veins. Forty patients (87%) had at least one lesion associated with pain (mean: 8⫾5 lesions, range 1 to 22 lesions) during ablation. The RF generator setting during lesions resulting in pain was 48.6⫾6.7 Watts (range 30 to 60) and 51.4⫾2.3 C° (range 41 to 55C°). Maximum temperature attained at the time of pain sensation was 45.7⫾ 3.2° C (range: 40 to 55°). The distribution of pain lesions for each vein and the distribution inside each vein are demonstrated in the Figure. The RF generator settings or maximum temperature of lesions resulting in pain was not different between the PVs. Conclusion: Pain is relatively common during RF ablation of PVs for AF. RF generator settings or maximum temperature of lesions resulting in pain was not different between PVs. Pain was more common during RF ablation of inferior PVs compared to the superior vein. The distribution of pain locations for each vein may reflect a higher density of the neural ganglionic plexi in the inferior, inferiomedial, and inferolateral aspects of the left atrium compared to the superior aspect.

S199 4-pulmonary vein isolation ( PVI ). Furthermore, several circuits of LAAFL anchoring in the LA may present as AF. Methods: A 16-slice multidetector computed tomography was used to image the LA and PVs in 44 patients with PAF ( 36 males, 50⫾12 y/o) before catheter ablation. After PVI and cavotricuspid isthmus linear ablation, inducibility of AF/AFL was assessed by rapid burst pacing from the proximal and distal coronary sinus with the high current and short pacing cycle length The lateral (from LIPV to the mitral annulus), and medial (from RIPV to the mitral annulus) isthmus length, presence of septal ridge, septal and LAA ridge length, LAA location (type I: LAA is superior to the LSPV, type II: LAA is horizontal to the LSPV, type III: LAA is inferior to the LSPV) and LA volume were examined (univariate and multivariate logistic regression analysis) to assess the predictor of AF/AFL inducibility. Results: In 24 (54%) patients, LA-AFL and AF were induced after PVI and they were eliminated after linear ablation on the mitral isthmus, LA anterior roof ( connecting to the LAA ridge ), and/or the LA septum. Univariate analysis showed LAA location and LA volumes were different between patients with inducible and noninducible AF/AFL (Table ). Multivariate analysis showed the inferior location of LAA was the only independent predictor for AF/AFL inducibility after PVI (Odds ratio 9.0). Conclusions: The isthmus between LAA and anterolateral mitral valve annulus would be smaller in patients with the inferior location of LAA; therefore, the smaller isthmus may be associated with a higher inducibility of AF/AFL.

Anatomic variables Lateral isthmus length (mm) Medial isthmus length (mm) Presence of septal ridge (%) Septal ridge length (mm) LAA ridge length (mm) LAA location I, II, III (%) LA volume (cm3)

Inducible AF/AFL

Noninducible AF/AFL

P value

33.5 ⫾ 8.0

29.8 ⫾ 5.5

⬎0.05

52.5 ⫾ 9.6 27 16.2 ⫾ 4.6 28.3 ⫾ 6.8 23, 32, 46 107 ⫾ 35

48.6 ⫾ 9.0 31 19.1 ⫾ 8.3 28.0 ⫾ 6.6 45, 45, 10 87 ⫾ 22

⬎0.05 ⬎0.05 ⬎0.05 ⬎0.05 0.017 0.03

P3-68

P3-67 DO THE ANATOMIC BARRIERS IN THE LEFT ATRIUM PLAY AN IMPORTANT ROLE FOR THE ATRIAL FLUTTER/FIBRILLATION INDUCIBILITY AFTER PULMONARY VEIN ISOLATION? 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: Information of the anatomic barrier in left atrium (LA) for LA flutter (AFL) is limited. Inducibility of LA-AFL and atrial fibrillation (AF) was frequently used to assess the results of catheter ablation after

SPONTANEOUS BAROREFLEX SENSITIVITY AFTER PULMONARY VEINS ISOLATION IN PREDICTING RECURRENCE OF ATRIAL FIBRILLATION Katarzyna Styczkiewicz, MD, Giammario Spadacini, MD, Massimo Tritto, MD, Paolo Moretti, MD, Giovanni B. Perego, MD, Mario Facchini, MD, Jorge A. SalernoUriarte, MD, PhD, Kalina Kawecka-Jaszcz, MD, PhD and Gianfranco Parati, MD, PhD. Jagiellonian University, Instituto Auxologico Italiano, Milano, Italy, Clinical Institute Mater Domini, University of Insubria, Castellanza, Italy, S. Luca Hospital, Instituto Auxologico Italiano, Milan, Italy, Circolo Hospital and Macchi Foundation, Varese, Italy, Jagiellonian University, Cracow, Poland and University of Milano, Bicocca and Instituto Auxologico Italiano, Milan, Italy. Aims: One of the hypothesis that justify the clinical success of pulmonary veins isolation (PVI) in curing atrial fibrillation (AF) assumes a denervating effect of RF lesions in PV ostia leading to changes in autonomic control of the heart (ACH). Our aim was to evaluate the effects of PVI on ACH and AF recurrences, assessed through the quantification of spontaneous baroreflex sensitivity (BRS). Methods: In 20 pts (16 M,4 F,age:60.4⫾5.3) undergoing PVI for AF, beat-to-beat BP monitoring was performed for 10 min 1-2 days before and 1 month after PIV. All pts were in sinus rhythm during each recording. The follow-up was 6 months. Baroreflex function was assessed by frequency domain BRS (Alpha coefficient and the modulus of PI/SBP transfer func-