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Use of nifekalant in cardioversion of patients with atrial flutter treated with or without class I antiarrhythmic agents
Poster 5 new technique in relation to the known predictors for prediction of recurrent AF after successful ECV. Methods: In total 43 patients underwent a trans-thoracic echocardiographic examination 3 days after successful ECV for measurement of the right and left atrial area and the LV ejection fraction . In addition we measured the PA-tdi-interval, defined as the time from the onset of the P-wave in the electrocardiogram (lead II) till the peak of the atrial tissue Doppler velocity curve from the lateral wall of the left atrium in the apical four chamber view. Patients with antiarrhythmic drugs (except low dose sotalol 40 mg bid) were excluded from the study. Endpoint was recurrence of AF one month after ECV. Results: During 1 month follow-up, AF recurred in 16 patients (37%). Patients with a recurrence of AF had a larger LA size compared to patients who remained in SR (47⫾ 4 versus 44 ⫾ 7ms, respectively, p⬍0.01). They also had a significantly longer PA-tdi interval compared to patients who remained in SR (174.80⫾ 52.76 versus 151.98 ⫾ 23.90 ms, respectively, p⬍0.01). Multivariate analysis demonstrated that the PA-tdi interval was the only independent predictor for recurrences of AF. Conclusion: The total atrial activation time as measured by atrial tissue Doppler imaging is able to identify an atrial substrate which is vulnerable for recurrent AF. This new parameter could become an easy to use tool for risk stratification in AF. P5-47 THE ROLE OF BACHMANN’S BUNDLE DURING CHRONIC ATRIAL FIBRILLATION IN PATIENTS WITH MITRAL VALVE DISEASE Natasja M. De Groot, MD, Pieter Voigt, MD, Jerry Braun, Martin J. Schalij, MD, PhD and Maurits Allessie. Leiden University Medical Center, Leiden, Netherlands and CardioVascular Research Institute Maastricht, Maastricht, Netherlands. Introduction: Animal studies have shown that bachmann’s bundle (BB) is essential for development of multiple reentrant circuits perpetuating atrial fibrillation (AF). Mapping of BB in humans has sofar not been performed. In this study, high density epicardial mapping of BB was performed to study conduction characteristics of fibrillation waves across BB during chronic AF in humans. Methods: Epicardial mapping studies of BB were performed in pts (n⫽10, age 58⫾3 yrs) with chronic AF during cardiac surgery for mitral valve disease with a template containing 60 unipolar electrodes (inter-electrode distance 1.5 mm). Ten seconds of AF were recorded from the middle (MBB), right (RBB) and left site of BB (LBB). Isochronal maps were off-line constructed. For each mapping site, AF cycle length (ACFL), conduction velocity (CV) and the incidence of conduction block (CV⬍ 7.5 cm/s) was determined. Fibrillation potentials were classified according to the degree of fractionation. Results: 3988⫾2039 fibrillation potentials and 197⫾56 fibrillation maps/pt were analysed. In most pts, multiple waves separated by arcs of conduction block were observed. In 3 pts, only single waves propagating at high CV were present. There were no preferential conduction directions. Electrophysiological variables are summarized in table 1. CV was slower and conduction block occurred more frequently at MBB compared to RBB and LBB (CV: MBB: 29⫾18cm/s* vs RBB:46⫾30cm/s, LLB: 52⫾20cm/s, p⬍0.02, conduction block: MBB:20⫾10%* vs RBB:5⫾3%, LLB:7⫾2%, p⬍0.01). Conclusion: There is a large inter-individual variation in activation patterns across BB during chronic AF in MVD patients. The results of this study suggest that BB is 1) a crucial pathway of conduction for fibrillation waves propagating from the right to the left atria or vice versa, or 2) a perpetuator of chronic AF.
S269 P5-48 PHARMACOLOGIC CARDIOVERSION OF ATRIAL FIBRILLATION WITH A EXTRA CLASS IC DOSING IN PATIENTS ALREADY ON DAILY MAINTENANCE CLASS IC THERAPY *James A. Reiffel, MD. Columbia University, New York, NY. The Class IC antiarrhythmic drugs (AAD) propafenone, in the immediate release form tid (P-IR) and sustained release form bid (P-SR), and flecainide (F) bid are often used to reduce or prevent episodes of atrial fibrillation (AF) in patients (pt) without structural heart disease or with uncomplicated hypertension, and may be initiated in the out-pt setting. The usual maximal daily dose (MDD) is 900 mg/d for P-IR, 850 mg/d forP-SR is 850 mg/d, and 400 mg/d for F. P-SR 650 mg/d and 850 mg/d respectively approximate the PK curves of P-IR at 450 mg/d and 675 mg/d. Single doses of P-IR (usually 600 mg) and F (usually 300 mg) have been used to terminate recent-onset AF in pt not taking an AAD with efficacy rates of 70-80% by 8 hrs. To determine whether extra doses of P-IR or F could be used to convert recurrent AF episodes in pt already taking daily P-IR, P-SR, or F, but at doses less than the MDD, 23 pt with 41 episodes were given single extra out-pt doses of P-IR or F at least 3 hours after their prior drug dose to raise their total dose of P or F for that day up to the MDD. For example, for P-IR 600 mg/d, a 300 mg “bolus” dose was used; for P-IR 450 mg/d, a dose of 300 mg was used, followed in 4 hrs by another 150 mg if needed. For P-SR of 325 mg bid, 300 mg of P-IR was used, but for 425 mg of P-SR bid, no more than 150 mg P-IR was used. 70% were men, average age 55; all new AF episodes were ⬍24 hrs long before the extra dosing. Results: For daily maintenance/acute dosing 3 pt used F/F, 5 pt used P-SR/P-IR, and 15 pt used P-IR/P-IR. Conversion rates were 64%, 71%, and 68%(p⫽ns). Adverse effects were mild (e.g., nausea, vague dizziness); there was no syncope, undue bradycardia, ventricular tachyarrhythmia. Conclusions: P-IR “bolus” dosing can be used to terminate recurrent AF in pt taking daily P-IR or P-SR, as can F in pts taking F, using the usual MDD as a guide to maximal additional dosing to be considered. Such additional doses appear to be as well tolerated as they are in pt not taking daily AAD. Efficacy rates may be slightly lower in pts taking daily doses of the same agents than in pts not yet on daily maintenance therapy. Confirmatory data in a still larger set of pt would be beneficial to clinical therapy. P5-49 USE OF NIFEKALANT IN CARDIOVERSION OF PATIENTS WITH ATRIAL FLUTTER TREATED WITH OR WITHOUT CLASS I ANTIARRHYTHMIC AGENTS Norishige Morita, MD, Yoshinori Kobayashi, MD, Kenji Yodogawa, MD, Yu-Ki Iwasaki, MD, Meiso Hayashi, MD, Mitsunori Maruyama, MD, Takuya Ono, MD, Yasushi Miyauchi, MD, Toshihiko Ohara, MD, Naoki Satoh, MD, Yoshiyuki Hirayama, MD, Hirotsugu Atarashi, MD, Keiji Tanaka, MD, Takao Katoh, MD and Teruo Takano, MD. Nippon Medical School, Tokyo, Japan. Background: Nifekalant(NIF) is pure class III antiarrhythmic agent (Ikr blocker) and proved to be effective in the treatment of ventricular arrhythmias. However whether or not it has effectiveness on atrial flutter(AFL) or class I antiarrhythmic agents induced AFL(I-AFL) converted from atrial fibrillation(AF) has not been understood well. Methods: This study consisted of 32 patients with total 38 episodes of AFL who had structural heart disease with LVEF of 44⫾16 %(26males, mean age: 68⫾11y/o) . NIF(0.3mg/kg) was administered for AFL, I-AFL, and AF. In 9 episodes the maintenance dose (0.2mg/kg/hr) was needed for the termination. Seventeen episodes(34%) out of all AFL were I-AFL. Results: NIF offered an overall AFL conversion efficacy of 89.4% (34 of 38 episodes). Termination rates of AFL and I-AFL by NIF were 85.7 and 94.1% respectively (n.s.). Four episodes of AF under prior treatment with NIF were converted to AFL with use of class I drugs by which all the AFLs were predisposed to the termination(100%). Termination rate of AFL lasting more than 72 hours tended to be lower than those lasting less than 72 hours(60.0% vs 93.9%, p⬍0.1). AFL cycle length(CL), QTc, and blood
S270 pressure after NIF were significantly increased without proarrhythmic events except for one TdP in whom QTc was 0.64 (QTc: 0.43⫾0.04 vs 0.49⫾0.06, p⬍0.05), but the degrees of increase in AFL CL and QTc did not differed between AFL and I-AFL groups (CL: 11.5% vs11.1% QTc: 14.2% vs11.3% n.s.). The termination modes of AFL and I-AFL were divided into two patterns;1) the abrupt termination of AFL with/without CL oscillation in 17 episodes(50%), 2) in the remaining episodes transient disorganization predisposed to the termination (50%). The former pattern was more prominent in AFL group compared to that in I-AFL group(61.1vs 37.5%, p⬍0.05). Conclusion: The use of NIF in AFL patients receiving class I agents is as successful in restoring sinus rhythm as the use in non-class I AFL. NIF ameliorate hemodynamics and have potent efficacy for AFL in structural heart disease with considerable safety. The termination mechanism by nifekalant may not be uniform as it was demonstrated with ibutilide. P5-50 SLOW PATHWAY ABLATION FOR AVNRT: A COMPARISON BETWEEN CRYOABLATION AND RADIOFREQUENCY ENERGY IN A 5-YEAR EXPERIENCE Isabelle Greiss, MD, Paul G. Novak, MD, Paul Khairy, MD, Laurent Macle, MD, Denis Roy, MD, Mario Talajic, MD, Bernard Thibault, MD, Peter G. Guerra, MD and Marc Dubuc, MD. Montreal Heart Institute, Montre´al, Quebec, Canada. Background: Re-entrant nodal tachycardias have been traditionally treated with radiofrequency energy (RF). Cryoablation is increasingly used for slow pathway (SP) ablation of AVNRT due to many potential advantages over RF. Long-term data on efficacy and safety comparing the two techniques are still limited. Methods: Retrospective data were collected in 128 consecutive cases of SP cryoablation performed between 1999 and 2004 and compared to 128 cases of SP ablation performed at the same center with RF. Results: Patients in the cryoablation group were younger than those in the RF group (42.6 versus 47.7 years; p⫽0.01), with no differences in gender or co-morbidities. Total procedure times were longer in the cryoablation (2.8 hr ⫹/- 0.9) compared to the RF group (2.1 hr ⫹/- 0.7) (p⬍0.0001). However, this difference was most likely protocol driven with a mandatory 30 minute observation period post ablation in a large number of patients in the cryoablation group. Fluoroscopy times were similar for cryoablation (20 min ⫹/- 15) and RF (18 ⫹/- 11) groups (p⫽ns). Overall, 111 patients in the cryoablation (86.7%) and 123 patients in the RF group (96.1%) had long-term success defined as failure of clinical tachycardia recurrence. However, 8 (6.3%) patients in the cryoablation group required cross-over to RF during the primary procedure. Therefore, 103 patients (85.8%) in the cryoablation group actually had a successful long-term cryoablation. There were no cases of permanent complete AV block requiring implantation of a permanent pacemaker in the cryoablation group and 1 case (0.8%) in the RF group. Conclusions: Slow pathway cryoablation leads to satisfactory but lower clinical success rates than RF energy for the treatment of AVNRT with a lower rate of complete AV block requiring permanent pacemaker implantation. The lower success rate may be due to a learning curve effect and requires further investigation. Overall, SP catheter cryoablation for AVNRT is effective and safe in a 5 year experience. P5-51 DELAYED RISK OF DEVELOPMENT OF ATRIOVENTRICULAR BLOCK AFTER SLOW PATHWAY ABLATION: A MULTICENTRIC RETROSPECTIVE STUDY Anahita Kowsar, MD, Thomas Arentz, MD, Marc Zimmerman, MD, Frederic Georger, MD, Pascal Defaye, MD, Serge Boveda, MD, Philippe Lagrange, MD, Cingiz Yldiz, MD, Luc De Roy, MD and Patrick Blanc, MD. CHU Limoges, Limoges, France, Herz Zentrum, Badkrozingen,
Heart Rhythm, Vol 2, No 5, May Supplement 2005 Germany, FMH Cardiologie, Switzerland, UCL Mt Gondine, Belgium, CHU, Grenoble, France, Toulouse, France, and CHU dupuytren, Limoges, France. Radiofrequency catheter ablation of the slow pathway for cure of Atrioventricular node reentry tachycardia (AVNRT) has been reported to be highly effective and safe, with an incidence of atrioventricular block (AVB) of ⬍ 1-5%.Few studies report a FU exceeded 20 months and never long term complications have been noted. Retac registry was done to evaluate the immediate results and the risk of development of delayed AVB after slow pathway ablation. Methods: This multicenter retrosprospective study was done for 1043 pts treated for recurrent, refractory AVNRT’s since many years (137 months). The mean FU is 40 months. The mean age was 52 years old and 67 % were females. Slow pathway ablation by radiofrequency application was attempted in all pts. Results: Persistent complete AVB occurred in 10 pts (0.9%), with immediate pace maker implantation. We have 3.2 % of recurrences. At the FU, 3 pts with II degree asymptomatic AVB after ablation were finally implanted 6 months later and 8 pts had paroxysmal AVB with PM implantation with a mean delay of 23 months. Two of these pts have had 2 and 3 ablation procedures for recurrences of AVNRT and one other have had 2 procedures for AVNRT and was ablated in add for an atrial flutter 6 month before AVB. Conclusions: Slow pathway ablation in pts with AVNRT is highly effective. Transient complete AVB is common and usually has a good prognosis. Definite complete AVB is rare (0.9 %). However, there is a risk of development of delayed AVB (1%) and the long-term FU remains necessary.
P5-52 PULMONARY VEIN STENOSIS AFTER OSTIAL CRYOISOLATION IN PATIENTS WITH ATRIAL FIBRILLATION? *Ju¨rgen Vogt, MD, Johannes Heintze, MD, Helga Buschler, MD, *Peter Schwartze, MD and Dieter Horstkotte, MD. Heart Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany. Pulmonary vein (PV) isolation with radiofrequency current (RF) as ablation source results in stenoses or occlusions in about 5% of patients (p) treated for paroxysmal atrial fibrillation (AF). Lesions created by cryoablation (C) are more homogeneous with the vascular architecture, particularly the intimal layer, remaining intact. The aim of this study was the assessment of PV anatomy after circumferential, single cryoimpulse (CI) isolation, or a combined technique regarding the manifestation of PV stenoses. In all p magnetic resonance angiography with gadolinium was performed before and every 3 months (mo) after cryoisolation. 52 p, 14 women, mean age 58⫾9 years, mean duration of AF 80⫾65 mo, 42 p with paroxysmal, 10 with persistent AF of, 9 with CAD, 13 with hypertension, 30 with idiopathic AF refractory to antiarrhythmic therapy, mean left atrium diameter 44⫾7 mm, were treated with the Arctic Circler (AC) alone, with a 6-mm cryotip catheter (Freezor xtra) or combined in order to close the ostial gaps. In 13 p the cryo procedure was a redo, in 10 p after Freezor xtra, and in 3 p after RF. 10 p had a single procedure with segmental ostial cryoisolation with Freezor xtra. 29 p were treated with the AC as a first intervention. The mean burden of segmental or circumferential cryoimpulses and of RF impulses was not significantly different (table). The mean follow-up period after primary 6-mm tip isolation, after 6-mm tip and following circumferential isolation with AC and after AC ablation as a first intervention were 18⫾1 mo, 14⫾2 mo and 11⫾3 mo, respectively. Even with this marked burden of cryoimpulses, no PV stenoses or narrowing were detected during serial follow-up. Circumferential and single pulse cryisolation of the PV is safe. Neither acute stenoses, shrinking nor proliferative structural remodeling were observed during long-term follow-up after cryoablation of the PV.
S269 P5-48 PHARMACOLOGIC CARDIOVERSION OF ATRIAL FIBRILLATION WITH A EXTRA CLASS IC DOSING IN PATIENTS ALREADY ON DAILY MAINTENANCE CLASS IC THERAPY *James A. Reiffel, MD. Columbia University, New York, NY. The Class IC antiarrhythmic drugs (AAD) propafenone, in the immediate release form tid (P-IR) and sustained release form bid (P-SR), and flecainide (F) bid are often used to reduce or prevent episodes of atrial fibrillation (AF) in patients (pt) without structural heart disease or with uncomplicated hypertension, and may be initiated in the out-pt setting. The usual maximal daily dose (MDD) is 900 mg/d for P-IR, 850 mg/d forP-SR is 850 mg/d, and 400 mg/d for F. P-SR 650 mg/d and 850 mg/d respectively approximate the PK curves of P-IR at 450 mg/d and 675 mg/d. Single doses of P-IR (usually 600 mg) and F (usually 300 mg) have been used to terminate recent-onset AF in pt not taking an AAD with efficacy rates of 70-80% by 8 hrs. To determine whether extra doses of P-IR or F could be used to convert recurrent AF episodes in pt already taking daily P-IR, P-SR, or F, but at doses less than the MDD, 23 pt with 41 episodes were given single extra out-pt doses of P-IR or F at least 3 hours after their prior drug dose to raise their total dose of P or F for that day up to the MDD. For example, for P-IR 600 mg/d, a 300 mg “bolus” dose was used; for P-IR 450 mg/d, a dose of 300 mg was used, followed in 4 hrs by another 150 mg if needed. For P-SR of 325 mg bid, 300 mg of P-IR was used, but for 425 mg of P-SR bid, no more than 150 mg P-IR was used. 70% were men, average age 55; all new AF episodes were ⬍24 hrs long before the extra dosing. Results: For daily maintenance/acute dosing 3 pt used F/F, 5 pt used P-SR/P-IR, and 15 pt used P-IR/P-IR. Conversion rates were 64%, 71%, and 68%(p⫽ns). Adverse effects were mild (e.g., nausea, vague dizziness); there was no syncope, undue bradycardia, ventricular tachyarrhythmia. Conclusions: P-IR “bolus” dosing can be used to terminate recurrent AF in pt taking daily P-IR or P-SR, as can F in pts taking F, using the usual MDD as a guide to maximal additional dosing to be considered. Such additional doses appear to be as well tolerated as they are in pt not taking daily AAD. Efficacy rates may be slightly lower in pts taking daily doses of the same agents than in pts not yet on daily maintenance therapy. Confirmatory data in a still larger set of pt would be beneficial to clinical therapy. P5-49 USE OF NIFEKALANT IN CARDIOVERSION OF PATIENTS WITH ATRIAL FLUTTER TREATED WITH OR WITHOUT CLASS I ANTIARRHYTHMIC AGENTS Norishige Morita, MD, Yoshinori Kobayashi, MD, Kenji Yodogawa, MD, Yu-Ki Iwasaki, MD, Meiso Hayashi, MD, Mitsunori Maruyama, MD, Takuya Ono, MD, Yasushi Miyauchi, MD, Toshihiko Ohara, MD, Naoki Satoh, MD, Yoshiyuki Hirayama, MD, Hirotsugu Atarashi, MD, Keiji Tanaka, MD, Takao Katoh, MD and Teruo Takano, MD. Nippon Medical School, Tokyo, Japan. Background: Nifekalant(NIF) is pure class III antiarrhythmic agent (Ikr blocker) and proved to be effective in the treatment of ventricular arrhythmias. However whether or not it has effectiveness on atrial flutter(AFL) or class I antiarrhythmic agents induced AFL(I-AFL) converted from atrial fibrillation(AF) has not been understood well. Methods: This study consisted of 32 patients with total 38 episodes of AFL who had structural heart disease with LVEF of 44⫾16 %(26males, mean age: 68⫾11y/o) . NIF(0.3mg/kg) was administered for AFL, I-AFL, and AF. In 9 episodes the maintenance dose (0.2mg/kg/hr) was needed for the termination. Seventeen episodes(34%) out of all AFL were I-AFL. Results: NIF offered an overall AFL conversion efficacy of 89.4% (34 of 38 episodes). Termination rates of AFL and I-AFL by NIF were 85.7 and 94.1% respectively (n.s.). Four episodes of AF under prior treatment with NIF were converted to AFL with use of class I drugs by which all the AFLs were predisposed to the termination(100%). Termination rate of AFL lasting more than 72 hours tended to be lower than those lasting less than 72 hours(60.0% vs 93.9%, p⬍0.1). AFL cycle length(CL), QTc, and blood
S270 pressure after NIF were significantly increased without proarrhythmic events except for one TdP in whom QTc was 0.64 (QTc: 0.43⫾0.04 vs 0.49⫾0.06, p⬍0.05), but the degrees of increase in AFL CL and QTc did not differed between AFL and I-AFL groups (CL: 11.5% vs11.1% QTc: 14.2% vs11.3% n.s.). The termination modes of AFL and I-AFL were divided into two patterns;1) the abrupt termination of AFL with/without CL oscillation in 17 episodes(50%), 2) in the remaining episodes transient disorganization predisposed to the termination (50%). The former pattern was more prominent in AFL group compared to that in I-AFL group(61.1vs 37.5%, p⬍0.05). Conclusion: The use of NIF in AFL patients receiving class I agents is as successful in restoring sinus rhythm as the use in non-class I AFL. NIF ameliorate hemodynamics and have potent efficacy for AFL in structural heart disease with considerable safety. The termination mechanism by nifekalant may not be uniform as it was demonstrated with ibutilide. P5-50 SLOW PATHWAY ABLATION FOR AVNRT: A COMPARISON BETWEEN CRYOABLATION AND RADIOFREQUENCY ENERGY IN A 5-YEAR EXPERIENCE Isabelle Greiss, MD, Paul G. Novak, MD, Paul Khairy, MD, Laurent Macle, MD, Denis Roy, MD, Mario Talajic, MD, Bernard Thibault, MD, Peter G. Guerra, MD and Marc Dubuc, MD. Montreal Heart Institute, Montre´al, Quebec, Canada. Background: Re-entrant nodal tachycardias have been traditionally treated with radiofrequency energy (RF). Cryoablation is increasingly used for slow pathway (SP) ablation of AVNRT due to many potential advantages over RF. Long-term data on efficacy and safety comparing the two techniques are still limited. Methods: Retrospective data were collected in 128 consecutive cases of SP cryoablation performed between 1999 and 2004 and compared to 128 cases of SP ablation performed at the same center with RF. Results: Patients in the cryoablation group were younger than those in the RF group (42.6 versus 47.7 years; p⫽0.01), with no differences in gender or co-morbidities. Total procedure times were longer in the cryoablation (2.8 hr ⫹/- 0.9) compared to the RF group (2.1 hr ⫹/- 0.7) (p⬍0.0001). However, this difference was most likely protocol driven with a mandatory 30 minute observation period post ablation in a large number of patients in the cryoablation group. Fluoroscopy times were similar for cryoablation (20 min ⫹/- 15) and RF (18 ⫹/- 11) groups (p⫽ns). Overall, 111 patients in the cryoablation (86.7%) and 123 patients in the RF group (96.1%) had long-term success defined as failure of clinical tachycardia recurrence. However, 8 (6.3%) patients in the cryoablation group required cross-over to RF during the primary procedure. Therefore, 103 patients (85.8%) in the cryoablation group actually had a successful long-term cryoablation. There were no cases of permanent complete AV block requiring implantation of a permanent pacemaker in the cryoablation group and 1 case (0.8%) in the RF group. Conclusions: Slow pathway cryoablation leads to satisfactory but lower clinical success rates than RF energy for the treatment of AVNRT with a lower rate of complete AV block requiring permanent pacemaker implantation. The lower success rate may be due to a learning curve effect and requires further investigation. Overall, SP catheter cryoablation for AVNRT is effective and safe in a 5 year experience. P5-51 DELAYED RISK OF DEVELOPMENT OF ATRIOVENTRICULAR BLOCK AFTER SLOW PATHWAY ABLATION: A MULTICENTRIC RETROSPECTIVE STUDY Anahita Kowsar, MD, Thomas Arentz, MD, Marc Zimmerman, MD, Frederic Georger, MD, Pascal Defaye, MD, Serge Boveda, MD, Philippe Lagrange, MD, Cingiz Yldiz, MD, Luc De Roy, MD and Patrick Blanc, MD. CHU Limoges, Limoges, France, Herz Zentrum, Badkrozingen,
Heart Rhythm, Vol 2, No 5, May Supplement 2005 Germany, FMH Cardiologie, Switzerland, UCL Mt Gondine, Belgium, CHU, Grenoble, France, Toulouse, France, and CHU dupuytren, Limoges, France. Radiofrequency catheter ablation of the slow pathway for cure of Atrioventricular node reentry tachycardia (AVNRT) has been reported to be highly effective and safe, with an incidence of atrioventricular block (AVB) of ⬍ 1-5%.Few studies report a FU exceeded 20 months and never long term complications have been noted. Retac registry was done to evaluate the immediate results and the risk of development of delayed AVB after slow pathway ablation. Methods: This multicenter retrosprospective study was done for 1043 pts treated for recurrent, refractory AVNRT’s since many years (137 months). The mean FU is 40 months. The mean age was 52 years old and 67 % were females. Slow pathway ablation by radiofrequency application was attempted in all pts. Results: Persistent complete AVB occurred in 10 pts (0.9%), with immediate pace maker implantation. We have 3.2 % of recurrences. At the FU, 3 pts with II degree asymptomatic AVB after ablation were finally implanted 6 months later and 8 pts had paroxysmal AVB with PM implantation with a mean delay of 23 months. Two of these pts have had 2 and 3 ablation procedures for recurrences of AVNRT and one other have had 2 procedures for AVNRT and was ablated in add for an atrial flutter 6 month before AVB. Conclusions: Slow pathway ablation in pts with AVNRT is highly effective. Transient complete AVB is common and usually has a good prognosis. Definite complete AVB is rare (0.9 %). However, there is a risk of development of delayed AVB (1%) and the long-term FU remains necessary.
P5-52 PULMONARY VEIN STENOSIS AFTER OSTIAL CRYOISOLATION IN PATIENTS WITH ATRIAL FIBRILLATION? *Ju¨rgen Vogt, MD, Johannes Heintze, MD, Helga Buschler, MD, *Peter Schwartze, MD and Dieter Horstkotte, MD. Heart Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany. Pulmonary vein (PV) isolation with radiofrequency current (RF) as ablation source results in stenoses or occlusions in about 5% of patients (p) treated for paroxysmal atrial fibrillation (AF). Lesions created by cryoablation (C) are more homogeneous with the vascular architecture, particularly the intimal layer, remaining intact. The aim of this study was the assessment of PV anatomy after circumferential, single cryoimpulse (CI) isolation, or a combined technique regarding the manifestation of PV stenoses. In all p magnetic resonance angiography with gadolinium was performed before and every 3 months (mo) after cryoisolation. 52 p, 14 women, mean age 58⫾9 years, mean duration of AF 80⫾65 mo, 42 p with paroxysmal, 10 with persistent AF of, 9 with CAD, 13 with hypertension, 30 with idiopathic AF refractory to antiarrhythmic therapy, mean left atrium diameter 44⫾7 mm, were treated with the Arctic Circler (AC) alone, with a 6-mm cryotip catheter (Freezor xtra) or combined in order to close the ostial gaps. In 13 p the cryo procedure was a redo, in 10 p after Freezor xtra, and in 3 p after RF. 10 p had a single procedure with segmental ostial cryoisolation with Freezor xtra. 29 p were treated with the AC as a first intervention. The mean burden of segmental or circumferential cryoimpulses and of RF impulses was not significantly different (table). The mean follow-up period after primary 6-mm tip isolation, after 6-mm tip and following circumferential isolation with AC and after AC ablation as a first intervention were 18⫾1 mo, 14⫾2 mo and 11⫾3 mo, respectively. Even with this marked burden of cryoimpulses, no PV stenoses or narrowing were detected during serial follow-up. Circumferential and single pulse cryisolation of the PV is safe. Neither acute stenoses, shrinking nor proliferative structural remodeling were observed during long-term follow-up after cryoablation of the PV.