AF Termination Research Articles

A High Baseline Electrographic Organization Level Is Predictive of Successful Termination of Persistent AtrialFibrillation by Catheter Ablation.

This study sought to investigate whether the level of organization of electrocardiographic (ECG) signals based on novel indexes is predictive of persistent atrial fibrillation (pAF) termination by catheter ablation (CA). Whether the level of ECG organization in pAF is correlated with the restoration of sinus rhythm by CA remains unknown. Thirty consecutive patients who underwent stepwise CA for pAF (sustained duration 19 ± 11 months) were included in the study (derivation cohort). ECG lead V6 was placed on the patients' back (V6b) to improve left atrial (LA) recording. Two novel ECG indexes were computed using an adaptive harmonic frequency tracking scheme: 1) the adaptive organization index (AOI), which quantifies the cyclicity of AF harmonic oscillations; and 2) the adaptive phase index (API), which quantifies the phase coupling between the harmonic components. Index cutoff values predictive of procedural AF termination were then tested on a validation cohort of 8 consecutive patients. In the derivation cohort, CA terminated AF in 21 patients within the LA (70%; left-terminated [LT] group), whereas CA did not terminate AF in 9 patients (30%; non-left-terminated [NLT] group). LT patients displayed a higher ECG organization level at baseline than the NLT patients, with the best separation achieved by AOI and API computed on lead V1 (area under the curve [AUC]= 0.94 and AUC= 0.88, respectively; p< 0.05) and API on lead V6b (AUC= 0.83; p< 0.05). Similar results were obtained for both AOI and API in the validation cohort. Patients in whom pAF terminated within the LA exhibited a higher level of atrial ECG organization, which was suggestive of a limited number of LA drivers than that of patients in whom the pAF could not be terminated by CA.

176-21: Divergent patterns of atrial ECG organization during catheter ablation of persistent atrial fibrillation revealed by adaptive harmonic frequency schemes

Introduction: We hypothesized that organization indices based on the analysis of atrial ECG harmonic components may help identify patients (pts) with persistent AF (pAF) unresponsive to pulmonary vein isolation (PVI) and left atrial (LA) ablation. Using adaptive harmonic frequency tracking schemes, we computed on the atrial ECG: 1) the variance of the phase difference (aPD) between the dominant frequency (DF) and the 1st harmonic (H1), and 2) the organization index (AOI) defined as the ratio of the power of the DF and H1 over the total power of the unprocessed atrial signal as measures of AF regularity. Methods: In 34 consecutive pts (61±7 y, pAF duration: 19±11 m), PVI and LA ablation were performed until AF termination. 40-sec ECG time series devoid of QRST were recorded at baseline (BL), after PVI (end_PVI) and at the end of LA ablation (end_ABL). APD and AOI were estimated on leads V1 and V6b (placed on the pts back). Results: pAF was terminated within the LA in 68% (23/34 LT - left terminated) of the pts, while 32% (11/34 NLT - not left terminated) did not. The figure shows that: 1) LT pts displayed higher AOI values at BL indicative of greater atrial ECG organization that increased significantly (p<0.05 for V1 and V6b) during LA ablation as opposed to NLT pts, and 2) NLT pts displayed higher APD values at BL indicative of greater atrial ECG disorganization that decreased during LA ablation, but did not reach LT pts values. Conclusion: Estimation of the level of organization of atrial ECG based on adaptive harmonic schemes appears as promising tools for the measure of pAF complexity and prediction of procedural outcome.

Nonlinear analysis of right atrial electrograms predicts termination of persistent atrial fibrillation within the left atrium by catheter ablation

The termination of long-standing persistent atrial fibrillation (LS-pAF) can be achieved by stepwise catheter ablation (step-CA) within the left atrium (LA). Our study aims to applying complexity measures derived from nonlinear time series analysis in order to characterize LS-pAF in terms of organization and to identify patients in whom AF can be terminated from those in whom AF cannot be terminated by step-CA within the LA. A total of 33 consecutive patients (age 61 ± 7 years, sustained AF duration 19 ± 11 months) with LS-pAF underwent step-CA. The organization of right bipolar electrograms before and during the ablation procedure was assessed using the coarse-grained correlation dimension. LS-pAF was terminated into sinus rhythm or atrial tachycardia in 22 patients during step-CA within the LA (left terminated patients—LT). In 11 patients the ablation procedure failed to terminate AF within LA (not left terminated patients—NLT). The statistical analysis of the estimated coarse-grained correlation dimension revealed that a higher right atrial (RA) organization before step-CA was associated to AF termination within the LA. During the ablation procedure, the level of RA organization displayed distinctive evolution between LT and NLT patients with a significant organization increase before AF termination for the LT patients.

Abstract 15904: Acute Outcomes in Persistent and Long-standing Persistent Atrial Fibrillation Patients Undergoing Rotor Ablation

Introduction: Focal impulse and rotor modulation (FIRM)-guided ablation targets localized sources that are thought to sustain AF. In previous reports, it has been shown that FIRM is effective in terminating or organizing AF. We sought to evaluate the acute success of FIRM in patients with persistent and LSP AF undergoing ablation in our centers. Methods: This was a multicenter prospective observational study. FIRM was performed alone or before conventional ablation. Rotors were ablated as confirmed by their absence during remapping and acute success was defined as AF termination, organization or slowing 10%. Results: 57 patients were enrolled (mean age 63 ± 10; 7% LSP). Rotors-only ablation was performed in 56% of patients, and preceded conventional ablation in 44%. There were no major periprocedural adverse events. No focal impulses were found, while rotors were present in all patients (3.9 ± 1.2 per patient; 66% in the LA). In the RA, the majority of rotors were in the lateral wall (53%) and in the septum (30%). In the LA, most of the rotors were in proximity of the pulmonary veins (48%), with the second most common locations being around the mitral annulus or in the septum (17% and 13% respectively). Mean procedural time for FIRM only procedures was 226 ± 52 minutes vs a median of 210 (168-240) minutes for FIRM + conventional ablation procedures (p = NS). Overall acute success was achieved in 35% of patients (3% AF termination, 16% AF organization, 16% AF slowing) with a mean RF time to complete FIRM ablation of 30 ± 15 minutes; no difference in acute success was found when comparing persistent to LSP patients (28% vs 50%; p = NS). Conventional ablation following FIRM did not significantly increase the rate of acute success (1 additional patient converted to sinus rhythm during pulmonary vein isolation). Conclusion: Rotors were present in all patients undergoing ablation for non-paroxysmal AF, most commonly the right atrial lateral wall, septum or around the pulmonary veins. Their ablation was not effective in obtaining AF organization/termination during the procedure.

Abstract 16017: Mid-term Outcomes in Persistent and Long-standing Persistent Atrial Fibrillation Patients Undergoing Rotor Ablation

Introduction: Focal impulse and rotor modulation (FIRM)-guided ablation targets localized sources that are thought to sustain AF. We sought to evaluate if acute success of FIRM-guided ablation in patients with non-paroxysmal AF influenced the mid-term ablation outcomes. Methods: This was a multicenter prospective observational study of persistent and LSP AF patients undergoing FIRM ablation in 3 centers. Patients with at least 2 months follow-up were included in the analysis. FIRM was performed alone or in addition to conventional ablation and rotors were ablated as confirmed by their absence during remapping. Acute success was defined as AF termination, organization or slowing 10%. Mid-term success was defined as freedom from AT/AF off antiarrhythmic drugs (AADs) and after a single procedure during the initial follow-up (excluding the 2-month blanking period). Results: A total of 43 patients were enrolled (mean age 62 ± 10; 91% persistent, 9% LSP). Rotors-only ablation was performed in 65% of patients, and in addition to conventional ablation in the remaining 35%. Overall, acute success was achieved in 33% of patients. During a mean follow-up of 5.5 ± 2.4 months, 35% of patients were free of AT/AF off AADs after a single procedure. When comparing patients who underwent rotors-only ablation with those who received additional conventional ablation, mid-term success rates were respectively 25% vs. 53% (P = NS). There was no statistical difference in SR maintenance between patients with and without acute success during FIRM ablation (29% vs. 38%, P = NS). Conclusion: FIRM-guided ablation in persistent and LSP AF was not effective in obtaining AF slowing/organization/termination during the procedure and in preventing mid-term AT/AF recurrences. Acute success did not impact the mid-term success rate.

Primary Persistent Atrial Fibrillation: A Distinct Arrhythmia Subentity of an Ablation Population.

Persistent atrial fibrillation (persAF) can occur either as a sustained arrhythmia that has progressed from initially paroxysmal AF or as primary persAF without a history of any spontaneously terminated episode. There is a paucity of data differentiating between the 2 different persAF entities. Thus, we prospectively evaluated baseline characteristics, electrophysiological features, and ablation outcome in these 2 patient cohorts. A total number of 154 consecutive persAF patients (63 ± 10 years, f = 42, longstanding persAF = 60) were characterized in terms of having primary persAF (P-persAF group) or persAF that secondarily progressed from paroxysmal AF (S-persAF group). All patients underwent de novo catheter ablation using the stepwise approach. PersAF entities were characterized by detailed patient history, sequential Holter monitoring, and reports of documented modes of AF conversion, respectively. The P-persAF group had a higher number of young patients (<50 years), a shorter AF history, and a higher number of congestive heart failure. The HATCH score did not differ between the groups. Procedural AF termination rate was significantly higher in S-persAF than in P-persAF patients (n = 55 [81%] vs. n = 58 [68%], P = 0.043). At 1-year follow-up, the arrhythmia-free survival after a single procedure was significantly lower in patients with P-persAF (26% vs. 43%, P = 0.016). Categorization to P-persAF was the strongest independent predictor of arrhythmia recurrence. P-persAF seems to be a specific arrhythmia entity that is associated with a lower AF-termination rate and a worse outcome after catheter ablation as compared to S-persAF.

Does isolation of the left atrial posterior wall improve clinical outcomes after radiofrequency catheter ablation for persistent atrial fibrillation?: A prospective randomized clinical trial

IntroductionAlthough posterior wall of left atrium (LA) is known to be arrhythmogenic focus, little is known about the effect of posterior wall isolation (PWI) in patients who undergo radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (PeAF). MethodsWe randomly assigned 120 consecutive PeAF patients to additional PWI [PWI (+), n=60] or control [PWI (−), n=60] groups. In all patients, linear ablation was performed after circumferential pulmonary vein isolation (PVI). Linear lesions included roof, anterior perimitral, and cavotricuspid isthmus lines with conduction block. In PWI (+) group, posterior inferior linear lesion was also conducted. Creatine kinase-MB (CK-MB) and troponin-T levels were measured 1day after RFCA. LA emptying fraction (LAEF) was assessed before and 12months after RFCA. ResultsA total of 120 subjects were followed for 12months after RFCA. There were no significant differences between two groups in baseline demographics and LA volume (LAV). The levels of CK-MB and troponin-T and procedure time were not significantly different between the groups. AF termination during RFCA was more frequently observed in PWI (+) than control (P=0.035). During follow-up period, recurrence occurred in 10 (16.7%) patients in PWI (+) and 22 (36.7%) in control (P=0.02). The change in LAEF was not significantly different between the groups. On multivariate analysis, smaller LAV and additional PWI were independently associated with procedure outcome. ConclusionsPWI in addition to PVI plus linear lesions was an efficient strategy without deterioration of LA pump function in patients who underwent RFCA for PeAF.

CONVERSION TO SINUS RHYTHM WITH IBUTILIDE DURING ATRIAL FIBRILLATION ABLATION IS NOT ASSOCIATED WITH LONG TERM SINUS RHYTHM MAINTENANCE

Identifying patients at higher risk of AF recurrence after successful ablation would help with selection of patients for more frequent post-ablation surveillance, more accurate individualized patient prognosis and decision regarding future management options such as anti-coagulation therapy. In patients who remain in AF after ablation, ibutilide is frequently used for restoration of sinus rhythm. In cases of failure to achieve SR with ibutilide, DCCV is used. We hypothesized that termination of AF with ibutilide defines a group of patients with a better long-term outcome. This is a retrospective observational study of 92 AF ablation procedures with drug-refractory symptomatic AF who were followed for a year by routine clinic visits in 3-6 month intervals or earlier in symptomatic patients. Recurrence and timing of atrial fibrillation during follow-up period was documented and compared among 3 groups of patients according to their response to ablation and administration of ibutilide at the time of ablation: spontaneous conversion to SR (SR group), SR conversion with ibutilide (IBU group) and those who required DCCV after ibutilide failure (IBU-DCCV group). The presence of paroxysmal AF (ORcrude=6.42, 95% CI 1.63-25.3, P=0.0079), absence of diabetes (ORcrude=5.60, 95% CI 1.15-27.26, P=0.03) and lower BMI (ORcrude=0.93, 95% CI 0.87-0.99, P=0.02, for 1 kg/m2 increase in BMI) were individually associated with spontaneous cardioversion after ablation. The median time to recurrence of AT/AF (time to failure) for SR, IBU and IBU-DCCV groups were 211, 162.9 and 83 days respectively. The survival curves for the groups were not statistically different (P=0.22) even after adjustment for potential confounders (Figure 1). Duration of RF ablation (HRCrude=1.014, 95% CI 1.001-1.027, P=0.034) and the time since AF diagnosis (HRCrude=1.117, 95% CI 1.046-1.193, P=0.001) were the only baseline parameters associated with AF recurrence after ablation. Conversion to SR with ibutilide is not associated with long-term rhythm maintenance after AF ablation. None of the baseline clinical or procedural parameters predicted the likelihood of successful cardioversion with ibutilide after AF ablation.

A Prospective and Randomized Comparison of Limited Versus Extensive Atrial Substrate Modification After Circumferential Pulmonary Vein Isolation in Nonparoxysmal Atrial Fibrillation

The optimal substrate ablation approach in patients with persistent atrial fibrillation (Per AF) remains unclear. This was a prospective randomized study comparing the efficacy of limited (continuous complex fractionated atrial electrogram, CFAE: <60 milliseconds) versus extensive (continuous CFAE plus variable CFAE: <120 milliseconds) atrial substrate modification in Per AF patients. We enrolled 120 Per AF patients in the study, and 30 patients with AF termination after pulmonary vein isolation (PVI) were excluded. In the remaining 90 patients, 45 were treated with limited approach (Group 1) and 45 with an extensive approach (Group 2). The end point of the study was the incidence of an atrial arrhythmia recurrence postblanking period. The patients were followed up for 15 months with 3-month clinical reviews, electrograms (ECGs), Holter recordings, and echocardiographic monitoring. Procedural AF termination and the single procedural efficacy were statistically comparable between the 2 groups (48.9% vs. 63.4% in Groups 1 and 2, respectively, P = 0.289). During the follow-up, patients who received limited ablation had a lower incidence of recurrent AFL (P = 0.04), and better reverse remodeling of the left atrium (LA, P = 0.04). After 2 procedures, the freedom from any atrial arrhythmia was better in Group 2 (62.2% vs. 87.8%, P = 0.009). Those with longstanding AF and a larger baseline LA size responded better to the extensive ablation. In the Per AF patients who failed to achieve AF termination after PVI alone, a specific atrial substrate modification approach targeting only continuous CFAEs could be considered as an initial ablation strategy.

PT005 Presence of thrombus in left atrium in patients with atrium fibrillation anticoagulated with coumarin anticoagulants versus dabigatran

O ST E R A B ST R A C T S theoretical and experimental studies, our group has shown that high bipolar electrogram Shannon entropy (ShEn) distinguishes the pivot and periphery of rotors. We hypothesised that ablation directed towards regions of high ShEn could slow or terminate AF. Objectives: The aim was to determine if directed ablation of regions of high ShEn would slow or terminate human persistent AF. Methods: The study enrolled 9 patients undergoing persistent AF ablation. (Left atrial diameter 45 6mm, LV ejection fraction 52 5%). Patients in spontaneous or induced AF were mapped with a 20-pole PentaRay catheter and NavX system. 8-second recordings of each mapped point were acquired, with endocardial contact verified by fluosocopy at each site. After mapping, mapped point electrophysiologic data and location data were exported to a PC where Shannon entropy (ShEn) was calculated for each mapped point. Points were ranked by entropy value, and colour-coded ShEn maps constructed. The top 10% of ShEn points were annotated on to the NavX map, and used to guide selection of regions for ablation. Ablation of pre-identified ShEn regions was performed after pulmonary vein antral isolation without CFAE or linear ablation. The study endpoints were: (i) AF cycle length change; and (ii) AF termination. Results: Mapping was able to be performed in all cases, with 621 26 points/pt acquired. AF termination occurred in 6/9 cases, with 3/9 cases requiring cardioversion. 5/9 cases showed AF termination co-localised with pre-specified regions of ShEn. In 3 of these cases, termination occurred at pre-specified regions of ShEn encountered during pulmonary vein antral isolation. In 2 cases,termination occurred at ShEn sites outside the pulmonary vein antra. Mean AFCL change post PV isolation was 11.8 13ms (p1⁄40.07), and AFCL change post-ShEn ablation was 29.1 26ms (p1⁄40.02). 6/9 cases remained in sinus rhythm at median follow-up 274 148 days . Sites of ShEn region termination included the base of LA appendage, right anterior wall, roof, posterior wall, and left superior PV ridge. Conclusion: The study demonstrates the feasibility of ablation of high ShEn regions, associated with termination of AF and/or AF cycle length slowing in selected AF patients, and requires further investigation in AF ablation. Disclosure of Interest: None Declared

Clinical outcome of ablation for long-standing persistent atrial fibrillation with or without defragmentation

ObjectiveTo assess the outcome and associated risks of atrial defragmentation for the treatment of long-standing persistent atrial fibrillation (LSP-AF).MethodsThirty-seven consecutive patients (60.4 ± 7.3 years; 28 male) suffering from LSP-AF who underwent pulmonary vein isolation (PVI) and linear ablation were compared. All patients were treated with the Stereotaxis magnetic navigation system (MNS). Two groups were distinguished: patients with (n = 20) and without (n = 17) defragmentation. The primary endpoint of the study was freedom of AF after 12 months. Secondary endpoints were AF termination, procedure time, fluoroscopy time and procedural complications. Complications were divided into two groups: major (infarction, stroke, major bleeding and tamponade) and minor (fever, pericarditis and inguinal haematoma).ResultsNo difference was seen in freedom of AF between the defragmentation and the non-defragmentation group (56.2 % vs. 40.0 %, P = 0.344). Procedure times in the defragmentation group were longer; no differences in fluoroscopy times were observed. No major complications occurred. A higher number of minor complications occurred in the defragmentation group (45.0 % vs. 5.9 %, P = 0.009). Mean hospital stay was comparable (4.7 ± 2.2 vs. 3.4 ± 0.8 days, P = 0.06).ConclusionOur study suggests that complete defragmentation using MNS is associated with a higher number of minor complications and longer procedure times and thus compromises efficiency without improving efficacy.

Role of Triggering Pulmonary Veins in the Maintenance of Sustained Paroxysmal Atrial Fibrillation

Triggers from thoracic veins have been implicated not only in the initiation, but also in the perpetuation of paroxysmal atrial fibrillation (PAF). To investigate their role we studied the distribution and stability of dominant frequencies (DFs) during PAF and the response to isolation of the triggering pulmonary vein (PV). Triggering structures inducing PAF were identified during isoproterenol challenge in 26 patients (15 males, 55 ± 8.5 years). During sustained PAF, sequential recordings were made with a decapolar circular mapping catheter from each PV and the left atrial posterior wall (LAPW), together with coronary sinus (CS) and right atrium (RA) recordings. DF was determined using fast Fourier transformation. Recordings were repeated after ≥15 minutes of PAF. Radiofrequency ablation was directed first at the triggering PVs. PAF initiated from the PVs in 24 patients and from RA in two. There was a significant frequency gradient from the triggering structure to the PVs, CS, LAPW, and RA (P < 0.0001). During the second recording, DF decreased at all sites (P < 0.02), but the frequency gradient remained unchanged. Despite isolation of the triggering PV, PAF continued in 53% of patients, although DF measured in the CS was lower. AF termination occurred with contralateral PV isolation in half of the remaining patients and further AF slowing was noted in the rest. Triggering structures harbor the fastest activity during sustained PAF pointing to their leading role in arrhythmia perpetuation. However, nontriggering PVs also seem to contribute to PAF maintenance.

Spatio-Temporal Differences in Bipolar Electrogram Characteristics: Shannon Entropy and Frequency Domain as Predictive Parameters of AF Termination

Spatio-Temporal Differences in Bipolar Electrogram Characteristics: Shannon Entropy and Frequency Domain as Predictive Parameters of AF Termination

Decrease of the atrial fibrillatory rate, increased organization of the atrial rhythm and termination of atrial fibrillation by AZD7009

BackgroundThe atrial fibrillatory rate (AFR), on AZD7009 as compared to placebo, was investigated as a potential biomarker for electrophysiological effect in early antiarrhythmic drug development. MethodsPatients with permanent AF received infusions of AZD7009 and placebo in an exploratory two-way, single-blind, randomized cross-over study. The ECG was continuously recorded, and following QRST cancellation the AFR, its standard deviation (SD), the exponential decay and the atrial electrogram amplitude were determined as 3-min averages. ResultsThe mean AFR rapidly decreased by 43% from baseline (394±38 to 225±61 fibrillations/min, p=0.0003) on AZD7009, but not on placebo. The SD of the AFR and the exponential decay decreased in parallel. In 2 of 8 patients, termination of AF occurred after the AFR had decreased by 58% and 53%, respectively. ConclusionsThe AFR may potentially serve as a biomarker of electrophysiological effects in early evaluation of rhythm control agents.

Abstract 9284: Selective Complex Fractionated Electrogram Targeting For Atrial Fibrillation Study (Select AF): A Multicenter, Randomized Trial

Introduction: This study compared pulmonary vein isolation (PVI) plus generalized CFAE ablation vs PVI plus selective CFAE ablation, specifically areas of continuous electrical activity (CEA)(ClinicalTrials.gov NCT00926783 ). Methods: Patients with persistent/high burden AF (age 63±9 yr, LA size 42±6 mm) were enrolled at 6 centers (n=86) &amp; randomized. For the generalized arm, all CFAE regions with an interval confidence level &gt;7 were ablated followed by PVI. For the selective arm, only those CFAE sites with CEA were ablated followed by PVI. For PVI, all PV antra were isolated with confirmed entrance block. Patients were followed with ECG, &amp; 48-hr Holter every 3 mos. AF symptoms were confirmed by loop recording. The primary endpoint was freedom from AF &gt;30 sec at 1 year. Results: Both generalized &amp; selective CFAE ablation prolonged AF cycle length (26±32 ms vs 22±33 ms, p=0.6). AF termination rates were also similar: 37% for generalized &amp; 31% for selective (p=0.6). In both groups, PVI was achieved after CFAE ablation in all patients. RF duration was significantly less in the selective arm vs the generalized arm (25±21 vs. 40±21 min, p=0.008). However, at 1 year follow-up, freedom from AF/AT recurrence was significantly higher in the generalized vs the selective arm after 1 procedure (59% vs 24%, p=0.005). Looking at AF/AT recurrence post 1st or repeat ablation, freedom from recurrence at one year in the generalized arm was 62%, still higher than 33% in the selective arm (p=0.02). There was a trend towards fewer repeat procedures in the generalized vs selective arm (14% vs 33%, p=0.057). Complications included tamponade (n=1) and a sedation-related event (n=1). Conclusions: In persistent/high burden AF, selective CFAE ablation + PVI results in similar AF cycle length prolongation and termination rates with significantly less RF time. However, long-term freedom from AF/AT is significantly better using generalized CFAE ablation + PVI.

Ablation of Persistent Atrial Fibrillation: AF Termination is the End Point.

This article reviews the literature on various techniques in the ablation of persistent AF, with the aim of highlighting the role of intraprocedural arrhythmia termination, defined as conversion to sinus rhythm or intermediate atrial tachycardia, in the predictability of arrhythmia recurrence. Because arrhythmia termination is not observed universally as a procedural end point, only those studies wherein it has been specifically reported, and its predictive role in arrhythmia recurrence is considered, are described.

203 Spectral analysis of intracardiac and surface electrocardiograms to determine the need for right atrial ablation in patients with chronic atrial fibrillation

It is not clear when to perform right atrial (RA) ablation in patients with chronic AF (CAF). The objective of this study was to compare the clinical and spectral characteristics of AF to identify predictors of RA ablation to terminate AF. In 12 patients (age 65 ± 6 years) with CAF, antral pulmonary vein isolation and ablation of complex fractionated atrial electrograms (CFAEs) were performed until AF terminated (within 120 minutes of radiofrequency energy application). In this retrospective analysis, patients were categorized in 3 groups: Group 1) Termination of AF with left atrial (LA) ablation only (n = 3); Group 2) termination of AF with left and right atrial ablation (n = 4); and Group 3) No termination after left and right atrial ablation (n = 5). Clinical characteristics and dominant frequency (DF) were compared at baseline and 1 min before termination of AF. The 3 groups were similar for all clinical variables, except for prior AF ablation which was more frequent in Group 2. (p = 0.02). At baseline, DF in V1 and CS were comparable in the 3 groups (Table). Only DF in the CS before termination was significantly different among the 3 groups (p = 0.04) and may be predictive of the need for RA ablation in these patients with chronic AF. Higher prevalence of repeat ablation procedures in patients who needed right atrial ablation may indicate that, right atrial drivers are under recognized during initial ablation. Therefore, right atrial drivers should be sought after during redo procedures for AF. Baseline V1 CS Termination with LA ablation 5.0 ± 1.0 5.6 ± 0.5 Termination with LA + RA ablation 4.4 ± 1.0 6.0 ± 0.5 No termination 5.3 ± 1.0 4.8 ± 1.2 p 0.4 0.3 Before termination V1 CS Termination with LA ablation 5.1 ± 1.0 4.8 ± 0.4 Termination with LA + RA ablation 4.8 ± 1.6 5.5 ± 0.5 No termination 4.4 ± 0.8 4.3 ± 0.7 p 0.7 0.04

The Characteristics of the Electrograms at the Site of AF Termination by Ganglionated Plexi Ablation

AF termination was often occurred during ganglionated plexi (GP) ablation. The purpose of this study was to characterize the electrograms at the site of AF termination by GP ablation. Method: Eighteen patients with AF termination by GP ablation were studied. In case of patients with sinus rhythm, AF was induced by rapid atrial pacing. The sites where vagal response was evoked by high-frequency stimulation were determined as GP sites and ablated. The bipolar electrograms were recorded in a 4.5-s window before the RF delivery. Result: AF termination was seen at superior left GP ablation in 3 patients, anterior right in 2 patients, inferior left in 6 patients, and inferior right (in 7 patients). Continuous electrical activity (CEA) was seen at the termination site in 16 (89%) patients. Other 2 patients without CEA, cycle length was 207±18 ms. The maximum duration of CEA was 1.8±0.3 of 4.5 sec. There were 2 patients with only CEA at the termination sites during all recording period. The maximum amplitude of CEA in 16 patients was 0.58±0.99 mV. Conclusion: The electrograms at the sites of AF termination by GP ablation show mainly transient CEA with relatively low voltage.

Impact of Preceded Pharmacological Cardioversion on Ablation Strategy of Persistent Atrial Fibrillation

Purpose: This study was aimed to investigate the ablation strategy for persistent atrial fibrillation (PerAF) which pharmacological cardioversion (PC) was tried before catheter ablation (CA). Methods: This retrospective study included consecutive 80 patients (63±9 years, 71 male) who underwent CA for PerAF (duration: 42±55 months). When sinus rhythm (SR) was maintained at the beginning of the procedure, extensive encircling pulmonary vein isolation (EEPVI), superior vena cava isolation (SVCI), and cavotricuspid isthmus block (CTIB) were done. If AF persisted after completion of EEPVI, atrial substrate ablation (ASA) was added until AF termination as its endpoint. Results: Thirty-nine patients for which PC was attempted were divided into 18 patients (46%, Group A) restored to SR, and 21 patients (54%, Group B) PC was failed. CA was performed during AF in 7, 19 patients of Group A, B (39 vs. 90%, p=0.001). Among these 7 patients with Group A, AF was terminated during EEPVI in 5, ASA at left atrial septum in 2, then finally converted to SR either directly or via CTI-dependent atrial flutter in all 7 patients. In contrast with Group B, AF termination during CA was achieved in 11 included 8 patients requiring ASA. During follow up of 3.1±1.3 months, AF-free rate was 83% in Group A, and 76% in Group B (p=0.54). Conclusion: CA mainly by thoracic vein isolation brought favorable outcome in PerAF patients with successful PC.

Clinical and Electrophysiological Variables Predictive of Favorable Outcome of Additional Ablation of Complex Fractionated Atrial Electrograms in Patients with Persistent Atrial Fibrillation

Introduction: The benefit of additional ablation of complex fractionated electrograms (CFE) has been reported in treating patients with persistent atrial fibrillation (per-AF). However, the ideal target patients group for this strategy remains unclear. We report a series of cases with per-AF in which addition of CFE ablation to PVI resulted in successful outcome in freedom from AF. Method and Results: Three patients with symptomatic per-AF (2 with lone AF and 1 with tachycardia-induced cardiomyopathy, AF duration 4–16 months, age 56±6 yrs, 3 male, LA diameter of 43, 46 and 49 mm) under went a single ablation with PVI plus CFE ablation using NavX. The amounts of CFE region were variable (12–34 cm2). However, the distribution was similar among patients (in both the LA roof toward the appendage and LA septum anterior to the right superior PV). All CFE regions were located along area with voltage of 0.5–1.0 mV. Although termination of AF was not achieved, the mean cycle length in the LA significantly prolonged by CFE ablation. Following a single procedure, all three patients remained in sinus rhythm at >4-months follow-up. Conclusion: The details of the clinical and electrophysiological characteristics underlying these three cases will be discussed.