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P6-54
Poster 6 previously described as maximal percentage prolongation of interatrial conduction time during atrial extra stimulation. Vulnerable atrium was considered if AF was inducible. DI⬎50%, repetitive atrial activity and fragmented electrograms was defined as susceptibility to vulnerability. Results: LAS ranged 10.5-36.6 cm2; 77 pts had trapezoidal LA. Simple regression analysis demonstrated a trend toward correlation between DI and LAS (r2⫽0.38, p⫽0.0001). ROC curve for prediction susceptibility to vulnerability was better than vulnerability to AF. The analysis demonstrates a cutoff value of 19.5 cm2 for LAS to detect susceptibility to vulnerability with a sensitivity of 89% and specificity of 90.5% (positive predictive value 93.4%; negative predictive value 84.4%). Using LAS ⬎25 cm2 as cut point, left atrial vulnerability to AF can be detected with a sensitivity of 56.2% and specificity of 95% (positive predictive value 81.8%; negative predictive value 83.3%). Trapezoidal LA was found in 72% pts with LAS⬎ 25 cm2 and 33% pts with LAS ⬍20 cm2. Conclusion: Left atrial dilatation and electrical remodeling are interrelated; progressive LA dilatation is accompanied with shape remodeling; characterization of LA remodeling should include LAS and shape definition.
P6-54 ELECTROPHYSIOLOGICAL PROPERTIES OF THE PULMONARY VEINS IN PATIENTS WITH AN ACCESSORY PATHWAY WITHOUT ATRIAL FIBRILLATION Lucas V. Boersma, MD, PhD, Fred H. Wittkampf, PhD, DS, Muchtiar Khan, MD and Eric F. Wever, MD, PhD. St. Antonius Hospital/HLCU, Nieuwegein, The Netherlands and UMCU/HLCU, Utrecht, The Netherlands. Introduction: The significance of pulmonary vein (PV) potentials (PVPs) for the arrhythmic mechanisms of AF, and whether PV isolation is a mandatory endpoint for RFCA is still debated. We therefore evaluated the characteristics of PV activity in pts without AF. Methods: Pts referred for RFCA of a left-sided accessory pathway (AP) and a second group of AF pts referred for PV isolation were included in the study. Transseptal puncture (8F) was done and PV angiography was performed. A decapolar LASSO™ catheter was used to register activity at the ostium and along the PV. PVPs were registered during basic pacing (BP) from the distal CS at 500 ms intervals, and during an extrastimulus (ES) at 300 ms interval. A PVP was defined as delay of ⬎5 ms between the LA and local PV activation. LocaLisa™ was used for 3D navigation and mapping. Results: 9 pts (5 male) were included with a mean age of 43⫾20 yrs (range 19 to 77). None had symptoms or a documented episode of AF. The AP was located left posteroseptal (3), left posterior (3), or left lateral (3), with pre-excitation in 7 pts. Angiography revealed 4 separate PVs in all pts. In 6 of 9 pts PVPs were seen during basic pacing in 25% of the PVs, being 4 LSPV, 3 LIPV, and 2 RSPV with a median delay between LA and local PVP of 5, 5, and 7 ms respectively. During an ES, PVPs appeared or increased in 2 LSPV, 1 RSPV, and 1 RIPV, with a median delay of 15, 17, and 15 ms respectively. The PVP did not increase when the Lasso catheter was inserted more distally until the catheter wedged or PVPs disappeared. In the AF group, 4 pts (3 male) with a mean age of 50⫾7 yrs (range 42 to 60) were studied. PVPs were seen in all 4 pts in 88% of PVs, with increased LA to PVP delay during an ES and when the LASSO was advanced. No distinct influence of age on these characteristics was observed within the group of AP pts, but pts in the AF group exhibiting PVPs were older than pts in the AP group. Conclusion: In contrast to pts with AF referred for PV isolation, individuals without evidence for AF have less prominent PVPs. Existing PVPs do not extend deep inside the vein and show little conduction delay or increase in delay during extrastimuli. These findings may relate to a lower propensity for AF. P6-55 A PROSPECTIVE EVALUATION OF VARIOUS METHODS OF ASSESSING RATE CONTROL IN PATIENTS WITH PERMANENT ATRIAL FIBRILLATION
S319 Emidio Tarulli, BSc, Iqwal Mangat, MD and Paul Dorian, MD. St. Michael’s Hospital, Toronto, Ontario, Canada. Background: Few studies have evaluated appropriate control of the ventricular rate (VR) during atrial fibrillation (AF). Since there is no accepted definition of rate control, assessing the adequacy of pharmacologic rate control is difficult. This clinical trial prospectively evaluated the correlation between VR as measured by resting 12-lead ECG, 24 hour Holter monitoring (HM), and during a six minute hall walk (HW) as well as the relationship between exercise capacity and VR control. Methods: Subjects with permanent AF on various VR control regimens underwent 12-lead ECG at rest followed by maximal exercise testing (EXT) using a modified Naughton protocol. They were then connected to HM and underwent HW and then continued HM for 24 hours. Results: Thirty-five subjects were enrolled: average age 65yrs, resting VR 81⫾14bpm, peak EXT VR 148⫾25bpm, peak HW VR 112⫾28bpm, mean HM VR 81⫾13bpm, and EXT duration 11.3⫾3.6min. Moderate correlations were noted between resting VR and both EXT duration and average HM VR (R⫽ -0.39, p⫽0.02, R⫽0.39, p⫽0.02). Standing VR correlated with average HM VR, maximum HM VR, peak EXT VR and peak HW VR (R⫽0..46, R⫽0.47, R⫽0.41, R⫽0.60; p⬍0.02 for all); however, it did not correlate with EXT duration. Resting VR correlated significantly with peak VR during HW (R⫽0.53, p⫽0.001), but did not correlate with HW distance. Peak VR during EXT did not correlate significantly with either EXT duration or HW distance (R⫽0.23, p⫽NS; R⫽0.25, p⫽NS). Figure 1 is a scatterplot of peak HW VR and resting VR, showing that a substantial number of patients (top left and bottom right quadrants) have incongruous indices of “good rate control”. Conclusion: Resting VR is predictive of EXT duration. Measurements of VR during HM, HW, and EXT are variably correlated, and are not reliable predictors of exercise capacity in patients with permanent atrial fibrillation.
P6-56 ASSOCIATION BETWEEN BRUGADA TYPE ELECTROCARDIOGRAM AND FAMILY HISTORY OF LONE ATRIAL FIBRILLATION Juhani Junttila, MD, Pekka Raatikainen, MD, Kai S. Lindgren, MD, Juha S. Perkio¨ma¨ki, MD, Ramon Brugada, MD and Heikki V. Huikuri, MD, PhD. University of Oulu, Oulu, Finland and Montreal Heart Institute, Montreal, Quebec, Canada. Background: Atrial arrhythmias are common among the patients with Brugada syndrome, and Brugada type 2 or 3 ECG abnormalities have also been observed in healthy subjects without any ventricular tachyarrhythmias (VT) or family history of sudden cardiac death (SCD). Therefore, we sought to examine, whether there exists a relationship between the Brugada type 2 or 3 ECGs and the family history of lone atrial fibrillation (AF). Methods: We analyzed ECGs of 220 consecutive patients with lone AF
P6-54 ELECTROPHYSIOLOGICAL PROPERTIES OF THE PULMONARY VEINS IN PATIENTS WITH AN ACCESSORY PATHWAY WITHOUT ATRIAL FIBRILLATION Lucas V. Boersma, MD, PhD, Fred H. Wittkampf, PhD, DS, Muchtiar Khan, MD and Eric F. Wever, MD, PhD. St. Antonius Hospital/HLCU, Nieuwegein, The Netherlands and UMCU/HLCU, Utrecht, The Netherlands. Introduction: The significance of pulmonary vein (PV) potentials (PVPs) for the arrhythmic mechanisms of AF, and whether PV isolation is a mandatory endpoint for RFCA is still debated. We therefore evaluated the characteristics of PV activity in pts without AF. Methods: Pts referred for RFCA of a left-sided accessory pathway (AP) and a second group of AF pts referred for PV isolation were included in the study. Transseptal puncture (8F) was done and PV angiography was performed. A decapolar LASSO™ catheter was used to register activity at the ostium and along the PV. PVPs were registered during basic pacing (BP) from the distal CS at 500 ms intervals, and during an extrastimulus (ES) at 300 ms interval. A PVP was defined as delay of ⬎5 ms between the LA and local PV activation. LocaLisa™ was used for 3D navigation and mapping. Results: 9 pts (5 male) were included with a mean age of 43⫾20 yrs (range 19 to 77). None had symptoms or a documented episode of AF. The AP was located left posteroseptal (3), left posterior (3), or left lateral (3), with pre-excitation in 7 pts. Angiography revealed 4 separate PVs in all pts. In 6 of 9 pts PVPs were seen during basic pacing in 25% of the PVs, being 4 LSPV, 3 LIPV, and 2 RSPV with a median delay between LA and local PVP of 5, 5, and 7 ms respectively. During an ES, PVPs appeared or increased in 2 LSPV, 1 RSPV, and 1 RIPV, with a median delay of 15, 17, and 15 ms respectively. The PVP did not increase when the Lasso catheter was inserted more distally until the catheter wedged or PVPs disappeared. In the AF group, 4 pts (3 male) with a mean age of 50⫾7 yrs (range 42 to 60) were studied. PVPs were seen in all 4 pts in 88% of PVs, with increased LA to PVP delay during an ES and when the LASSO was advanced. No distinct influence of age on these characteristics was observed within the group of AP pts, but pts in the AF group exhibiting PVPs were older than pts in the AP group. Conclusion: In contrast to pts with AF referred for PV isolation, individuals without evidence for AF have less prominent PVPs. Existing PVPs do not extend deep inside the vein and show little conduction delay or increase in delay during extrastimuli. These findings may relate to a lower propensity for AF. P6-55 A PROSPECTIVE EVALUATION OF VARIOUS METHODS OF ASSESSING RATE CONTROL IN PATIENTS WITH PERMANENT ATRIAL FIBRILLATION
S319 Emidio Tarulli, BSc, Iqwal Mangat, MD and Paul Dorian, MD. St. Michael’s Hospital, Toronto, Ontario, Canada. Background: Few studies have evaluated appropriate control of the ventricular rate (VR) during atrial fibrillation (AF). Since there is no accepted definition of rate control, assessing the adequacy of pharmacologic rate control is difficult. This clinical trial prospectively evaluated the correlation between VR as measured by resting 12-lead ECG, 24 hour Holter monitoring (HM), and during a six minute hall walk (HW) as well as the relationship between exercise capacity and VR control. Methods: Subjects with permanent AF on various VR control regimens underwent 12-lead ECG at rest followed by maximal exercise testing (EXT) using a modified Naughton protocol. They were then connected to HM and underwent HW and then continued HM for 24 hours. Results: Thirty-five subjects were enrolled: average age 65yrs, resting VR 81⫾14bpm, peak EXT VR 148⫾25bpm, peak HW VR 112⫾28bpm, mean HM VR 81⫾13bpm, and EXT duration 11.3⫾3.6min. Moderate correlations were noted between resting VR and both EXT duration and average HM VR (R⫽ -0.39, p⫽0.02, R⫽0.39, p⫽0.02). Standing VR correlated with average HM VR, maximum HM VR, peak EXT VR and peak HW VR (R⫽0..46, R⫽0.47, R⫽0.41, R⫽0.60; p⬍0.02 for all); however, it did not correlate with EXT duration. Resting VR correlated significantly with peak VR during HW (R⫽0.53, p⫽0.001), but did not correlate with HW distance. Peak VR during EXT did not correlate significantly with either EXT duration or HW distance (R⫽0.23, p⫽NS; R⫽0.25, p⫽NS). Figure 1 is a scatterplot of peak HW VR and resting VR, showing that a substantial number of patients (top left and bottom right quadrants) have incongruous indices of “good rate control”. Conclusion: Resting VR is predictive of EXT duration. Measurements of VR during HM, HW, and EXT are variably correlated, and are not reliable predictors of exercise capacity in patients with permanent atrial fibrillation.
P6-56 ASSOCIATION BETWEEN BRUGADA TYPE ELECTROCARDIOGRAM AND FAMILY HISTORY OF LONE ATRIAL FIBRILLATION Juhani Junttila, MD, Pekka Raatikainen, MD, Kai S. Lindgren, MD, Juha S. Perkio¨ma¨ki, MD, Ramon Brugada, MD and Heikki V. Huikuri, MD, PhD. University of Oulu, Oulu, Finland and Montreal Heart Institute, Montreal, Quebec, Canada. Background: Atrial arrhythmias are common among the patients with Brugada syndrome, and Brugada type 2 or 3 ECG abnormalities have also been observed in healthy subjects without any ventricular tachyarrhythmias (VT) or family history of sudden cardiac death (SCD). Therefore, we sought to examine, whether there exists a relationship between the Brugada type 2 or 3 ECGs and the family history of lone atrial fibrillation (AF). Methods: We analyzed ECGs of 220 consecutive patients with lone AF