1) Mean BP decreased significantly (p � 0.001) with increased degrees ofirregularities, and 2) SNA tended to be greater as irregularity increased.Conclusion: The decrease in blood pressure associated with an irregularventricular response is greater as the degree of irregularity increases. Theeffect of restoring a regular ventricular response on hemodynamics andSNA in patients with chronic AF remains to be determined.

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Favorable arrhythmia prognosis in patients with a firstshort lasting episode of atrial fibrillationKlaartje L. Merckx, MD, Robert G. Tieleman, MD, PhD andHarry J. Crijns, MD, PhD. Univ Hosp Maastricht,Maastricht, Netherlands.

Background: RACE and AFFIRM have demonstrated that rhythm controlis not superior to rate control in patients with recurrent atrial fibrillation(AF). This may partly be due to patient selection bias and low maintenanceof sinus rhythm (SR) in the rhythm control group (39% and 62% SR,respectively), despite extensive use of potentially dangerous anti-arrhyth-mic drugs. Little is known about the arrhythmia prognosis of patients withfirst time AF of short duration.Methods: We investigated maintenance of SR in all new AF patients(episode duration �24 hours) from 2001 and 2002 after their first cardio-version of AF.Results: 61 patients (age 64 � 14 years; 54 males) came to our emergencyroom with first time AF. Underlying heart disease was hypertension with LVH(34%), valve disease (28%), coronary artery disease (21%). AF was lone in of44% patients. Seven patients converted spontaneously to SR while waiting inthe ER. In 52 of the remaining 54 patients (96%) SR was restored by iv.flecainide. In the 2 patients in whom flecainide failed, SR was restored byelectrical cardioversion. At discharge 15 patients (25%) received sotalol 80 mgbid to prevent recurrent AF, no other anti-arrhythmic drugs were prescribed.After a mean follow period of 500 � 206 days, only 10 patients (16%) showeda recurrence of AF. In 1 patient AF recurred within the 1st month. The mediantime to recurrence of AF was 197 days, range 20-603 days.Conclusion: In patients with a first episode of AF �24 hours in duration,maintenance of sinus rhythm in the present study (84%) is far better than inrecently published randomized trials of rhythm versus rate control, despitelower use of prophylactic anti-arrhythmic drugs. Therefore, every patient witha first episode of AF deserves a least 1 attempt to restore SR within 24 hours.

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Symptoms and quality of life in patients suffering fromatrial fibrillation with and without moderate heart failure:Data from a prospective trial comparing rate versusrhythm control*Gerian C. Groenefeld, MD, Juergen Lilienthal, PhD and*Stefan H. Hohnloser, MD. J. W. Goethe Univ, Frankfurt,Germany and Datamap GmbH, Freiburg, Germany.

Background: The PIAF trial was the first prospective randomized trialcomparing rate versus rhythm control as primary treatment strategy inpatients (pts) with persistent atrial fibrillation (AF). Recent data suggestthat symptomatic response to either strategy might depend on the concom-itant presence of congestive heart failure (CHF).Methods: In PIAF, pts with symptomatic AF of 7-365 days duration wererandomized to control of ventricular rate alone or to cardioversion and main-tenance of sinus rhythm (SR). This post-hoc analysis stratified patients accord-ing to New York Heart Association functional status (group A: NYHA I vs.group B: NYHA II-III), and, in a second analysis, according to echo-derived leftventricular shortening fraction (SF), lowest (Q1) versus highest quartile (Q4).Results: 252 pts were randomized, of whom 137 were in NYHA class II-III.Analysis of symptomatic response on intention-to-treat basis yielded no dif-ference between group A (69/115 � 60%) versus group B pts (77/137 � 56%p � ns), irrespective of the primary treatment assignment. For pts on rhythmcontrol therapy, SR maintenance did not differ between group A (29/62 �47%) versus group B pts (26/65 � 40%; p � ns). Further stratification

according to the primary treatment strategy (Table 1) revealed a better im-provement in exercise tolerance with rhythm control in both quartiles of SF.Quality of life (SF-36 scores), in contrast, showed marked improvement onlyin patients with reduced shortening fraction, irrespective of the treatmentstrategy.Conclusion: These findings show no significant differences between symp-toms, exercise tolerance, and SR maintenance between pts with and with-out moderate CHF. Of note, improvement in quality of life was found onlyin pts with reduced SF.

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Frequency of supraventricular arrhythmias in patientswith the Brugada syndromeRainer Schimpf, MD, Lars Eckhardt, MD, Fiorenzo Gaita,MD, Christian Wolpert, MD, Carla Giustetto, MD, FrancescaBianchi, MD, Gunter Breithardt, MD and Martin Borggrefe,MD, PhD. Mannheim, Germany, Munster, Germany,Ospedale Mauriziano Umberto I, Turino, Italy, Univ ofMannheim, Mannheim, Germany and Univ of Munster,Munster, Germany.

Supraventricular tachycardias namely atrial fibrillation is often associated withseveral types of structural heart disease or has a familial origin with a hered-itary defect. The association of atrial fibrillation with the long QT syndrome,the Brugada syndrome and the short QT syndrome could only recently beshown. The percentage of supraventricular tachycardias in Brugada syndromehas been estimated with approximately 10%. Aim of this actual study is theevaluation of the distribution and frequency of supraventricular tachycardias inpatients in a large cohort of patients with Brugada syndrome.Patients and methods: 115 consecutive patients (mean age 45 � 12 years,men n � 92, women n � 33) were enrolled into the study. 19 (17%)patients were survivors of sudden cardiac death, 58 patients (50%) hadsyncope, 33(29%) a positive family history of sudden cardiac death. In 26patients (23%) supraventricular tachycardias could be detected (AV nodalreentry tachycardia n � 8, WPW-syndrome n � 2, atrial tachycardias n �3). Furthermore, spontaneous atrial fibrillation was documented (11.3%)and in 9 patients atrial fibrillation could be induced at EP-study (8%).Clinical implications: 1) 23 % of patients with Brugada Syndrome havesupraventricular tachycardias. 2) AF is associated with Brugada syndromein 13%. 3) In cases of atrial fibrillation especially in the young patientsBrugada syndrome has to be ruled out.

ABSTRACT SESSION 19: CATHETER ABLATION III: Ablation ofVentricular Tachycardia in Patients with Structural Heart DiseaseFriday, May 21, 20048:00 a.m.–9:30 a.m.

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Ablation of ventricular tachycardia in patients withcoronary artery disease: Advantages of the CARTO mapduring sinus rhythmMatthias Antz, MD, Katharina Berodt, Feifan Ouyang, MD,Dietmar Bansch, MD, Anselm Schaumann, MD, Sabine Ernst,MD, Peter Falk, Marius Volkmer, MD and Karl-Heinz Kuck,MD. St. Georg General Hosp, Hamburg, Germany.

For ablation of ventricular tachycardia (VT) in patients with coronary arterydisease a three dimensional mapping system is frequently used. Mapping isperformed either during VT or sinus rhythm/pacing (SR). We compared thesetwo mapping strategies in 94 patients using the CARTO system.

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Methods and results: VT-mapping was performed during induced stableVT (32 patients) or stable incessant VT (14 patients) with identification ofthe critical area of slow conduction using diastolic potentials and concealedentrainment pacing. For SR-mapping (48 patients) the following strategywas used: first pathological myocardium was identified by fragmented, lateand/or low amplitude (�1.5 mV) bipolar potentials. Then pace mappinginside or at the boarder of this pathological myocardium was performedduring SR in order to identify the VT exit. The catheter remained at thearea with the best match between stimulated QRS and VT-QRS, ideally ata site with a long stimulus to QRS interval. Afterwards VT was inducedand the critical site was confirmed by local diastolic potentials during VTand–if possible–VT termination by radiofrequency (RF) current delivery.Patients with SR map were not significantly different from patients withVT map in regard to age (65 � 9 vs 65 � 8 years), VT-cycle length (397 �82 vs 419 � 98 msec), number of RF applications (17 � 8 vs 17 � 10applications) and ablation result, i.e., non inducibility of any VT (69 vs43%), inducibility of only non clinical VT (27 vs 39%), or with the clinicalVT remaining inducible (4 vs 18%). However, procedure duration andfluoroscopy time were significantly shorter in the SR group as compared tothe VT group (391 � 117 vs 460 � 147 min (p � 0.05) and 21 � 10 vs32 � 22 min (p � 0,05), respectively).Conclusion: When using a CARTO guided approach for VT ablation inpatients with coronary artery disease, SR mapping is as successful asmapping during VT. However, ablation based on the SR map has theadvantage of shorter procedure time and shorter fluoroscopy time and maytherefore be considered as the mapping and ablation strategy of choice.

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Relationship of post infarction ventricular tachycardia exitsites to the scar border: Implications for catheter ablation*David J. Wilber, MD, Joseph B. Morton, MBBS, John J.Cai, MD, *Martin C. Burke, DO, *Albert C. Lin, MD, *SeanP. Tierney, MD, *Peter A. Santucci, MD, Koji Azegami, MDand *Mauricio Arruda, MD. Loyola Univ Medical Ctr,Maywood, IL.

Improvement in substrate-based approaches to ablation of post infarctiontachycardia (VT) requires better understanding of the relationship of VTcircuits to landmarks identifiable during sinus rhythm (SR). We examinedthe relationship of VT circuits to the scar border, and the potential role ofSR pacing along the scar border to identify target sites for ablation.Methods: In 27 pts with prior infarction (age 66 � 11 yrs; ejection fraction30 � 10%), electroanatomical activation and voltage mapping (Biosense/Webster) and entrainment studies were performed during 35 stable VTs(mean cycle length [CL] 410 � 56 ms). Exits sites (ExS) were defined asthose with electrogram-QRS intervals �30% of the VT CL, concealedentrainment during pacing in VT, and a postpacing interval within 30 msof the VT CL. ExS were tagged, and the relationship to the scar border (1.5mv isopotential line) noted. Pacemaps (PM) were obtained at the taggedExS during SR. PM were scored in each of 12 leads based on similarity tothe VT morphology (2 � exact match, 1 � minor differences in notchingor amplitude, 0 � major differences in polarity). Linear lesions were thenplaced approximately 1 cm inside and parallel to the scar border during SR,incorporating the ExS, using sequential radiofrequency applications withan open irrigation 3.5 mm electrode.Results: In 32/35 VTs (91%), an ExS could be identified within 1.5 cm ofthe scar border. In 1 pt, the ExS was deeper in the scar, and in 2 pts noendocardial ExS could be identified. In 29/32 VTs with an ExS adjacent tothe scar border, a similar QRS morphology (PM score 22-24) was obtainedat the same site during SR pacing. In all 32 VTs with an ExS adjacent tothe scar border, linear ablation in SR eliminated reinduction of VT. Only2/32 VTs (6%) ablated in this fashion recurred during a median follow-upof 17 mo.Conclusions: The ExS for most post infarction stable VT circuits arelocated near the scar border, and can be identified by SR PM. Linear scarborder ablation guided by PM during SR may be applied to unstable VT aswell, for which these data provide “proof of concept”.

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Ablation of unmappable post-MI ventricular tachycardiausing substrate mapping during sinus rhythm: Predictorsfor a recurrence*Hiroshi Nakagawa, MD, PhD, Dalip Singh, MD, Karen J.Beckman, MD, Deborah J. Lockwood, MBBS, Sunny S. Po,MD, PhD, Richard Wu, MD, Hiroshi Aoyama, MD, PhD,Sara Foresti, MD, Sameer Oza, MD, Lisa Herring, RN,James D. Calame, RN, Ralph Lazzara, MD and *Warren M.Jackman, MD. Cardiac Arrhythmia Research Inst, Univ ofOklahoma HSC, Oklahoma City, OK.

Isolated bundles of surviving myocardium within the scar form critical com-ponents of ventricular tachycardia (VT) reentrant circuits in pts with prior MI.Isolated bundles can be identified during sinus rhythm (SR) as sites of isolatedlate ventricular potentials (ILPs, usual amplitude only 0.05-0.2 mV) within thescar which is represented by an area of low bipolar voltage (�0.5 mV).Ablation of ILPs during SR markedly reduces or eliminates unmappable VTsin pts with prior MI. We postulated that the timing of ILPs and size of lowvoltage area may predict ablation success.Methods and Results: 22 pts (age 38-75 years) with prior MI and frequentepisodes of multiple, unmappable VTs were studied. A high density elec-troanatomical map (median 343 mapped points, CARTO) of the LV en-docardium was obtained during SR. Within the low bipolar voltage area(�0.5 mV), recordings were obtained at 2-3 mm intervals where possible.All ILPs within the low voltage area were targeted for RF ablation. VTrecurred within 2 years in 5/22 pts (although ICD therapies decreasedpost-ablation from 13-150 to 0.2-2 per month). The area of low voltage(�0.5 mV) was significantly smaller in the 5 pts with VT recurrence,compared to the 17 pts without VT recurrence: 6-90 (median 23) cm2 vs.6-144 (median 67) cm2, p � 0.05. The low voltage area was �30 cm2 in4/5 pts with VT recurrence and in only 3/17 pts without VT recurrence. Thelatest ILP (measured from the onset of QRS) was significantly earlier in the5 pts with VT recurrence, compared to the 17 pts without VT recurrence:130-227 (median 175) ms vs 145-511 (median 272) ms, p � 0.01. The latestILP was �230 ms in all 5 pts with VT recurrence and in only 5/17 pts withoutVT recurrence. 7/22 pts had both criteria (area of low voltage �30 cm2 andlatest ILPs �230 ms) and 4/7 (57%) pts had VT recurrence. In contrast, VTrecurred in only 1/15 (7%) pts without both criteria. LVEF was similar in ptswith and without VT recurrence (26 � 5% vs 25 � 10%).Conclusions: Ablation of unmappable post-MI VT by targeting ILPs dur-ing SR is highly effective in pts with a large low voltage area. Pts with alow voltage area �30 cm2 and ILPs �230 ms are likely to have a VTrecurrence.

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Preventive ablation of post infarction ventriculartachycardias: Results of a prospective randomized studyJurgen Schreieck, MD, Michael A. E. Schneider, MD,Michael Rohling, Bernhard Zrenner, MD, Isabel Deisenhofer,MD, Jun Dong, MD, Christof Kolb, MD, Christian Von Bary,MD, Martin R. Karch, MD and Claus Schmitt, MD, PhD.Klinik fur Herz-Kreislauferkrankungen, DeutschesHerzzentrum Munchen, TU Munchen, Muenchen, Germany.

Background: Catheter ablation of drug refractory ischemic ventriculartachycardias (VT) have become more effective by creating linear lesionsconnecting scars or separating VT exit points. The value of a preventiveVT ablation in post infarction patients was investigated by a prospective,randomized trial.Methods: 39 post infarction patients (age: 65 � 9 years, left ventricularejection fraction: 33 � 14%) with an indication for ICD implantation dueto VTs were randomized for ablation of VTs and ICD implantation or forICD implantation only. All patients underwent an electrophysiologicalstudy with programmed ventricular stimulation to test inducibility of VTs.In patients referred for ablation (n � 19) the exit points of all documentedor inducible VTs were defined by pace mapping in sinus rhythm. Radio-

S36 Heart Rhythm, Vol 1, No 1, May Supplement 2004

frequency current applications (21 � 11) with cooled-tip or large tipablation catheters were used to separate VT exit points along the border ofscar tissue guided by electroanatomical voltage mapping (CARTO, n � 11)or non-contact mapping (EnSite, n � 8). After the ablation procedere 74%of patients had no inducible VT at all and in 95% of patients the clinicallydocumented VT could not be induced any more. Control (n � 20) andablated patients received no other antiarrhythmic drugs besides from�-blockers after ICD-Implantation.Results: After a mean follow-up of 11.3 � 8.9 months 47% of the ablatedpatients and 60% of the control patients had a VT recurrence. The numberof VT episodes requiring an ICD intervention were significantly lower inthe ablation group (3.7 � 6.3) than in the control group (10.2 � 18.8).Conclusion: The preliminary results of our ongoing trial demonstrates thatpreventive substrate-orientated VT ablation in post infarction patients doesnot reduce the recurrence rate of VTs. However, the frequency of VTepisodes requiring treatment by the ICD was clearly reduced.

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Electroanatomical mapping and ablation of VentricularFibrillation (VF) in patients with IschemicCardiomyopathy (ICM)Atul Verma, MD, Nassir F. Marrouche, MD, Oussama M.Wazni, MD, Fethi Kilicaslan, MD, Jennifer E. Cummings,MD, J. David Burkhardt, MD, Yaariv Khaykin, MD,Mandeep Bhargava, MD, Johannes Brachmann, MD, JensGuenther, Antonio Rossillo, MD, Antonio Raviele, MD, SakisThemistoclakis, MD, Steven Hao, MD, Salwa Beheiry, MDand Andrea Natale, MD. The Cleveland Clinic Foundation,Cleveland, OH, Klinikum Coburg, Coburg, Germany,Umberto I Hosp, Mestre, Italy and Marin Heart Ctr, SanFrancisco, CA.

Background: Ablation of PVC triggers along the Purkinje system maysuccessfully eliminate VF in patients with normal hearts, long QT, andBrugada syndromes. However, whether such a mechanism and ablativeapproach would be applicable to VF in ICM is unknown.Objective: We assessed the impact of PVC mapping and ablation inpatients with VF storm refractory to drug and ischemic heart disease.Methods: Eight consecutive patients with VF storm (mean 52 � 25episodes) refractory to medical therapy and ICM (mean EF 15 � 4%) wereidentified; 7 had ICDs and 1 had an LVAD. All patients had initiation ofVF documented on multichannel telemetry monitoring and all underwent3D electroanatomical mapping using the CARTO system. Induction se-quences of spontaneous and isoproterenol-induced episodes of VF werestudied. Areas of scar were identified using voltage mapping if no PVCswere seen during the procedure. Ablation was performed using a cooled tipcatheter. Follow-up was done by Holter and ICD interrogation.Results: In 5 of 8 patients, mapping of unimorphic PVC similar to thespontaneous PVC was performed. PVC mapping showed that the earliestactivation site was consistently located in the scar border zone. The PVCwas always preceded by a Purkinje-like potential (mean 68 � 30 mspre-PVC). Ablation was performed at these sites with successful oblitera-tion of the PVC. In the other 3 patients, infrequent PVCs preventedactivation mapping, but Purkinje-like potentials were seen in the borderzone. Ablation was therefore performed around the scar border with thegoal of eliminating all Purkinje-like potentials. Mean followup of 10 � 6months revealed no VF recurrence; one patient developed sustained, mono-morphic VT.Conclusions: VF in ICM appears to be triggered by monomorphic PVCsoriginating from the scar border zone with preceding Purkinje-like potentials;targeting these inciting PVCs or Purkinje-like potentials along the scar bordermay prevent VF recurrence. In this subgroup substrate mapping and ablationcould be considered when PVCs are not seen during the ablation.

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Mapping and ablation of polymorphic ventriculartachycardia after myocardial infarction

Lukasz J. Szumowski, MD, PhD, Prashanthan Sanders, MD,PhD, Franciszek Walczak, MD, PhD, Roman Kepski, PhD,Ewa Szufladowicz, MD, PhD, Meleze Hocini, MD, PiotrUrbanek, MD, Robert Bodalski, MD, Pawel Derejko, MDand Michel Haıssaguerre, MD. Inst of Cardiology, Warsaw,Poland and Hopital Cardiologique du Haut-Leveque,Bordeaux-Pessac, France.

Background: The mechanisms of polymorphic ventricular tachycardia(PVT) after myocardial infarction (MI) are unclear. Migrating scrollwaves, intramural reentry and Purkinje network activity have been postu-lated.Method: 5 pts (4M, 61 � 7yrs) with recurrent episodes of PVT afteranterior MI (LVEF 32 � 7%) despite adequate revascularization werestudied. Pts were selected on the following basis: (i) frequent ventricularpremature beats (VPB) and (ii) initiation of PVT by VPB. Mappingidentified the earliest site of activity during VPBs or used pace mappingtechniques during sinus rhythm, and was confirmed by the elimination ofVPBs by ablation. Purkinje origin of VPB was defined by a sharp spike(Purkinje potential; PP) preceding VPB. Electroanatomic voltage mappingwas performed in sinus rhythm to define the MI border zone in relation toablation sites.Results: In all pts, the earliest site of activity during VBPs was locatedwithin the MI border zone and preceded by PP (details in table). Purkinjeectopy were observed to demonstrate variable PP to muscle conduction andblock. Ablation at these sites eliminated all VPBs. In addition, in 3 pts withmonomorphic VT, ablation was also performed at other sites using con-ventional criteria in the MI border zone. During a follow up of 15 � 5months using defibrillator memory interrogation, no patient has had recur-rence of arrhythmiaConclusions: This study demonstrates the crucial role of triggers arisingfrom the distal Purkinje arborization in the development of PVT after MI.It demonstrates the feasibility of mapping and ablation to eliminate thesetriggers, with consequent suppression of clinical arrhythmia.

ABSTRACT SESSION 20: NONINVASIVE EVALUATION IV: NoninvasiveRisk StratificationFriday, May 21, 200410:30 a.m.–12:00 p.m.

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T wave alternans identifies low risk patients who may notbenefit from ICD therapy*Daniel M. Bloomfield, MD, Richard C. Steinman, BA,Pearila B. Namerow, PhD, Michael Parides, PhD, ElizabethS. Kaufman, MD, Anne B. Curtis, MD, John Fontaine, MD,Andrea M. Russo, MD and J. Thomas Bigger, Jr., MD.Columbia Univ College of Physicians and Surgeons, NewYork, NY and Columbia Univ, New York, NY.

We are conducting a prospective longitudinal study to test the hypothesisthat T wave alternans is associated with an increased rate of mortality inpatients with left ventricular dysfunction (LVD). Recently, the Centers for

S37Session 20