Redo Catheter Ablation Research Articles

Acute and long-term outcome of redo catheter ablation for recurrent atrial tachycardia and recurrent atrial fibrillation in patients with prior atrial fibrillation ablation.

Organized atrial tachycardia (AT) accounts for a substantial proportion of recurrence after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). We sought to analyze the characteristics and long-term outcome of redo RFCA for recurrent AT compared with those for recurrent AF. We analyzed 133 patients who underwent prior AF ablation and presented for redo RFCA procedure. Documented rhythm at recurrence was AT in 50 patients (37.6%) and AF in 83 patients (62.4%). Redo ablation was conducted using a stepwise approach in all subjects. Recurrent arrhythmia was more frequently a persistent type in the AT group (70.0% vs. 36.1% in the AT and AF group, respectively, p < 0.001). Fifty mappable ATs were identified in the AT group. Perimitral reentry was most common (19/50), followed by PV-related focal or reentrant tachycardia (16/50). During the redo RFCA, PV reconnection rate and linear ablation rate were similar in the two groups, while the focal target ablation tended to be conducted more frequently in the AF group (26.0% vs. 42.2%, p = 0.060). The AT group showed a higher acute success rate (92.0% vs. 75.9%, p = 0.019) and higher arrhythmia freedom during a mean of 30months (76.0% vs. 55.4%, p = 0.030), compared with the AF group. The AT group and de novo AF type (paroxysmal) were independent predictors for higher arrhythmia freedom. RFCA for recurrent AT following AF ablation showed favorable acute and long-term success rates and was associated with superior procedural outcomes compared with those for recurrent AF.

Hybrid surgical ablation for persistent or long standing persistent atrial fibrillation: A French single centre experience

BackgroundHybrid ablation for the treatment of atrial fibrillation is a single combined procedure consisting in a minimally thoracoscopic surgical ablation followed by a catheter ablation. This promising technique is recommended in persistent atrial fibrillation according to the current guidelines but is not routinely performed in France, mainly due to the absence of reimbursement by the French National Health Insurance. AimsThe aim of this prospective and single-centre study was to analyse, for the first time in France, the feasibility, efficacy and complication rates of hybrid ablation in patients with persistent atrial fibrillation. MethodsHybrid ablation was performed in 15 consecutive patients (13 men, mean age 61±6 years) with persistent (7 patients) or long standing persistent (8 patients) atrial fibrillation. ResultsHybrid ablation was completed in 14/15 patients. Eleven patients returned in sinus rhythm during the procedure. Two patients (13%) had major per-procedural complications and 2 had minor complications. During an average follow-up of 25±6 months, 6 patients (40%) underwent a redo catheter ablation because of atrial tachycardia, mainly peri-mitral atrial flutter. At 1 year follow up, 14/15 patients were in sinus rhythm, including 11 free of antiarrhythmic drugs.

554 Atrial mechanical dispersion in patients with atrial fibrillation undergoing catheter ablation: a strain study

Abstract Background Atrial mechanical dispersion (MD) might increase the risk of atrial fibrillation (AF). However, the data on atrial mechanical dispersion in patients with AF undergoing catheter ablation (CA) are scarce. Purpose To describe effects of CA on inter- and left intra-atrial MD in patients with different sub-types of AF undergoing CA. Methods We prospectively enrolled 138 symptomatic patients (age: 63 ± 21 years, 32% females) with paroxysmal AF undergoing first (81%) or redo (19%) CA during sinus rhythm, and 20 individuals (age: 66 ± 23 years, 20% females) with long-standing persistent AF undergoing first CA during AF. All patients had normal (≥50%) left ventricular ejection fraction. Control group consisted of 23 healthy controls. The atrial strain and strain rate (SR) were assessed using the two-dimensional speckle tracking echocardiography as average of segmental values in all apical views for LA and in four chamber (4CH) apical view for RA. We quantified inter-atrial MD as the standard deviation of time from the onset of the P wave to peak negative strain curves (Figure 1), and left intra-atrial MD as the standard deviation of time from the onset of QRS wave to peak positive strain curves (Figure 2) of all LA segmental components in 4CH apical view after setting adjusting the reference frame to coincide with the onset of the QRS. Results Figure 3 shows a time course of reservoir LA strain and left intra-atrial MD in patients with paroxysmal AF undergoing the First-CA (3A) versus the Redo-CA (3B), and in patients with long-standing persistent AF (3C). At 1-day pre-ablation, patients with long-standing persistent AF showed significantly lower reservoir strain of both atria and higher left intra-atrial MD as compared with both paroxysmal AF groups and controls (all p &amp;lt; 0.01). The Redo-CA versus the First-CA group showed significantly lower LA reservoir strain (p &amp;lt; 0.01) while left intra-atrial MD was similar. RA reservoir strain and inter-atrial MD was similar between groups with paroxysmal AF. At 1-day post-ablation, we observed a significant deterioration of reservoir LA strain and left intra-atrial MD only in the First-CA group. After 3- month follow-up, left intra-atrial synchrony was significantly improved compared with pre-ablation in both groups of paroxysmal AF undergoing the first CA and long-standing persistent AF (p &amp;lt; 0.05). The reservoir LA strain showed partial recovery to pre-ablation values in paroxysmal AF undergoing first-CA while it showed a continuous improvement in long-standing persistent AF. In contrast, patients with paroxysmal AF undergoing redo-CA did not show significant improvement in any of these indices. Inter-atrial MD and RA strain did not show significant improvement in either group. Conclusion Atrial strain and MD shows distinct behavior in patients with different sub-types of AF post CA. Atrial MD may provide a complimentary information to strain when assessing LA function. Abstract 554 Figure.

P2451Patterns of left atrial structural and functional remodeling after catheter ablation in paroxysmal and long-standing persistent atrial fibrillation

Abstract Background Both atrial fibrillation (AF) and catheter ablation (CA) may be associated with changes in left atrial (LA) structure and function. However, the data describing acute and short-term effects of CA on LA contractile function in different sub-types of AF are scarce. Purpose First, to describe patterns of LA structural and functional remodeling in patients with paroxysmal AF (PAF) or long-standing persistent AF (LSPAF) undergoing first or redo CA. Second, to assess clinical feasibility of LA strain and strain rate (SR) to monitor effect of AF and CA on LA contractile function. Methods We prospectively enrolled 138 consecutive patients (age: 63±21 years, 32% females) with PAF undergoing first (81%) or redo (19%) CA during sinus rhythm, and 20 individuals (age: 66±23 years, 20% females) with LSPAF undergoing first CA during AF. All patients were symptomatic and preserved (≥50%) left ventricular ejection fraction. Control group consisted of 23 healthy controls. All patients underwent comprehensive echocardiography one day pre-CA and post-CA, and at 3 month follow-up. The LA reservoir, conduit and contractile longitudinal strain (LAS) and LASR were assessed using 2D speckle tracking echocardiography as average of segmental values in apical views. Results A total of 14 (9%) patients had insufficient image quality for LA assessment and were excluded (feasibility: 91%). Pre-CA, patients with LSPAF showed the largest left atrial volume index (LAVI) (45±14 ml/m2), followed by PAF (35±8 ml/m2) and controls (24±10 ml/m2) (p&lt;0.001). The lowest reservoir and contractile LAS was observed in patients with LSPAF (12±5% and 0%), followed by PAF undergoing redo CA (22±7% and 9±4%), versus first CA (27±8% and 13±4%) and controls (37±7% and 16±4%) (p&lt;0.001). LASR followed similar trend. Post-CA, we observed acute increase of LAVI in all groups (figure 1). Reservoir and contractile LAS and LASR decreased only in patients with PAF who underwent first CA. In contrast, it remained unchanged in individuals with PAF who had redo CA or even increased in subjects with LSPAF (figure 2). At 3 month follow-up, LAVI was significantly reduced compared with baseline in all groups of patients with AF (p&lt;0.01). In contrast, LAS and LASR did not show uniform improvement in all AF groups and on average they remained significantly lower compared with controls (p&lt;0.01). The lowest LAS and LASR values were observed in patients with PAF who underwent redo CA (no improvement from baseline) and in patients with LSPAF (significant improvement versus baseline) (figure 2). Patients with PAF who had the first CA showed higher LAS and LASR compared with other two AF groups (p&lt;0.01) but still significantly lower than controls (p&lt;0.01). Conclusion Different sub-types of AF show different patterns of LA structural and functional remodeling after CA. Both reservoir and contractile LAS appear highly feasible and reproducible to monitor LA contractile function in this clinical setting.

P5695Catheter ablation of ventricular tachycardia in patients with acute vs. previous myocarditis

Abstract Background Ventricular tachycardias (VT) may occur late after myocarditis, as well as in the acute inflammatory phase of the disease. However, the role of catheter ablation (CA) in preventing VT recurrences in patients with acute (AM) vs. previous myocarditis (PM) has never been investigated so far. Purpose To evaluate the results of CA performed in patients presenting with VA and biopsy-proved myocarditis at different inflammatory stages. Methods We enrolled 46 consecutive patients (74% males, mean age 43±12y, mean LVEF 46±9%) with myocarditis and VT at index hospitalization. Based on endomyocardial biopsy and cardiac magnetic resonance (CMR) results, the patients were divided into AM and PM groups: in AM group, myocarditis was biopsy-proved, according to the ESC criteria; PM patients had a history of biopsy-proved myocarditis more than 12 months before, with no current signs of active inflammation (negative biopsy according to the ESC criteria; nonischaemic LGE at CMR with negative Lake-Louise criteria; absence of unexplained troponin abnormalities). ICD were implanted upon clinical indications. All of the patients underwent electroanatomical mapping (EAM) and VT CA. During 3 (2.5–3.5)y FU, VT recurrences were evaluated by 2/y Holter ECG and ICD interrogation. Results At baseline, 23 patients (50%) had AM, and 23 PM. Overall, 16 AM and 21 PM patients underwent ICD implant (p=n.s.). The clinical VT was monomorphic in 22 AM and 23 PM patients, respectively (p=n.s.) with a dominant right-bundle branch block with superior axis (RS) morphology in both groups (16 AM vs. 17 PM cases, p=n.s.). However, RS morphology was associated with left ventricular inferoposterior LGE at CMR in 9/16 AM vs. 17/17 PM patients (p=0.003). Similarly, inferoposterior localization of low-voltage areas at EAM was found in 11/16 AM vs. 17/17 PM patients (p=0.018). Furthermore, CMR showed a greater LGE transmural extension in AM patients (65±19%) as compared to PM ones (40±25%, p&lt;0.001). Epicardial EAM and CA were performed in 14 AM vs. 15 PM patients, with endocardial-only approach adopted in the remaining cases (p=n.s.). VT CA was defined as successful (class A) in all of the subjets. However, during FU VT recurrences were documented in 7/23 AM vs. 0/23 PM patients (p=0.009). Four AM cases underwent redo CA late after myocarditis (1.5±0.3y after index hospitalization), with no further VT recurrences in FU. Conclusion In myocarditis patients presenting with VT, CA results are significantly better in PM cases as compared to AM ones. These findings are consistent with the different underlying substrate, and suggest the best role for ablation strategy after myocarditis healing. Acknowledgement/Funding None

Complications of the Catheter Treatment of Atrial Fibrillation: Stenosis of All Pulmonary Veins after Radiofrequency Ablation

Radiofrequency ablation is the "gold standard" in atrial fibrillation treatment. The frequency of complications is about 3.5-3.9 %. The symptomatic pulmonary vein stenosis is one of the most severe complications. In this report we present a clinical case of stenosis of all four pulmonary veins after redo catheter ablation of atrial fibrillation in 61year-old patient, and discussion of possible causes, specific features of diagnosis, and possible approaches to treatment of this complication.

Long-term outcomes after "Zero X-ray" arrhythmia ablation.

Radiation exposure related to conventional tachyarrhythmia radiofrequency catheter ablation (RFCA) carries small but definite risk for both patients and operators. Today, non-fluoroscopic mapping systems enable to perform catheter ablation with minimal or zero fluoroscopy. The purpose of this study was to evaluate the long-term outcome of patients who had undergone "Zero X-ray" ablation, since no information is available on the very long-term benefits. A total of 272 arrhythmias in 266 patients have been treated with catheter ablation by means of a zero-ray approach guided only by a nonconventional mapping system (EnSite NavX™, Ensite™ Velocity™ mapping system; subsequently Ensite™ Precision™ Abbott, St. Paul, MN). Fluoroscopy was never used. Over a period of 6years, patients were followed up for an average of 2.9 ± 1.6years. A 100% rate of acute success was observed in the study population, with a complication rate of 0.8%. Chronic success was achieved in 90.8% of the total number of procedures (272). Patients in whom the same arrhythmia recurred during follow-up underwent to a redo catheter ablation procedure in 60.0% of cases, while the remaining 40.0% underwent pharmacological treatment. A new post-ablation arrhythmia occurred in 7.7% of the sample. The non-fluoroscopic approach is a feasible and safe alternative to fluoroscopy for arrhythmias ablation. This method ensures low complications rates, high acute procedural success rates, and comparable long-term outcomes with clinical benefits for both patients and physicians. The complete elimination of fluoroscopy during catheter ablation is advantageous and does not reduce patient safety.

Three-year follow-up of hybrid ablation for atrial fibrillation.

The single-step hybrid atrial fibrillation (AF) ablation procedure combines a transvenous endocardial and thoracoscopic epicardial approach in 1 procedure. Short-term results are encouraging, but long-term outcome data are not available. Hybrid AF ablation was successfully performed in 64 consecutive patients (53% with persistent AF). The mean follow-up period was 1732 ± 353 days. Perprocedural endocardial touch-up of incomplete epicardial lesions was performed in 17 (26%) patients. In paroxysmal AF patients, arrhythmia-free cumulative survival rates after 1 hybrid AF ablation without Class I or III antiarrhythmic drugs procedure and without redo catheter ablation were 83%, 80% and 80% after 1, 2 and 3 years, respectively. In (long-standing) persistent AF patients, these were 82%, 79% and 79% after 1, 2 and 3 years. Thirteen (20%) patients had at least 1 recurrent episode of supraventricular arrhythmia lasting longer than 30 s: the most frequent recurrent arrhythmias were left atrial flutter and AF. No mortality or conversion to cardiopulmonary bypass, no phrenic nerve palsy and no pacemaker implantation were reported. Hybrid AF ablation, combining a transvenous endocardial and thoracoscopic epicardial approach in a single procedure, results in a cumulative 3-year freedom from arrhythmia without Class I or III antiarrhythmic drugs and without redo catheter ablation of 80% in paroxysmal AF (24 of 30 patients) and 79% in non-paroxysmal AF (26 of 33 patients).

0170: Long-term success with magnetic navigation catheter ablation in patients with persistent and longstanding persistent atrial fibrillation

Different techniques in catheter ablation (CA) of persistent (Pers) and longstanding (LS) Pers AF have been described with variable outcomes. We report long-term results in a series of Pers AF patients who underwent CA with magnetic navigation (MN). We prospectively included 50 patients (pts; 43 males; 61±10 y) referred for CA of Pers AF. Pers and LS Pers AF were defined according to published guidelines. Freedom from AF is defined as the absence of symptomatic or ECG/Holter documented AF after ablation. All pts underwent stepwise CA using MN: circumferential pulmonary veins isolation, bi-atrial complex fragmented electrograms ablation, roof ± left isthmus ± cavo-tricuspid isthmus lines. Atrial tachycardia (AT) occurring during CA were also targeted. Total duration of AF history was 56±42m (range 4 m-12 y, median 48m). Mean duration of continuous AF was 8±12m (range 1-84m, median 5.5m; 18% LS and 82% Pers AF). AF was lone in 50%. LA size was 30±5cm 2 , CT-scan volume 139±51ml. Procedures’ duration was 256±56 minutes with a fluoroscopy time of 13±5 min. RF time was 47±27 min. AF stopped without electrical cardioversion in 17 pts (34%; sinus rhythm in 8 and AT in 9). A redo CA for recurring AF was performed in 6 pts (12%). Complications (4 pts) resolved w/o sequellae: acute coronary syndrome (1), pericardial effusion (1), AV fistula (1) and intraalveolar haemorrhage (1). After 19.9±9.5m (range 6-40, median 17.5m), with 1.1 procedures/pt, 40 pts (80%) had no AF recurrence, of which 28 were off AAD and 12 remained on AAD. Incidence of postablation AT was 12% (6/50). Magnetic navigation for Pers AF ablation yields excellent (80%) long-term (20m) prevention of AF recurrence (figure next page). Abstract 0170 – Figure: AF-free survival

AV block after flutter ablations?

A 68-year-old, otherwise healthy male, presented at the emergency department with dizziness and near-syncope 4 days after a redo catheter ablation procedure for atypical right atrial flutter. In 1980 he underwent surgical closure of an atrial septal defect. One year prior to the current problem, a catheter ablation procedure in the right atrium was performed because of an atypical isthmus-dependent atrial flutter. During this procedure the cavotricuspid isthmus was blocked. Four days before presentation at the emergency department, a redo procedure was performed because of another postincisional atrial flutter. This time the flutter circuit was located in the septum and was successfully ablated. The earlier ablation lines were well recognisable and still formed block. Physical examination and laboratory tests did not demonstrate any abnormalities.

Iatrogenic atrial septal defects following atrial fibrillation transcatheter ablation: a relevant entity?

The previous literature has suggested that the iatrogenic atrial septal defects (IASDs) may follow left atrial (LA) access by transseptal (TS) puncture, especially in the case of a single TS for more than one catheter. The aim of the present study is to describe the prevalence of patent foramen ovale (PFO) and IASDs in a cohort of atrial fibrillation (AF) patients undergoing redo catheter ablation (CA) procedures in a high-volume centre accessing LA by a standardized single TS puncture. Patients (n = 197) who underwent at least one redo AFCA, between 2004 and 2012, were retrospectively enroled. Transoesophageal echocardiography was performed before each procedure during which LA was accessed via a PFO, if present, or by single TS for both the mapping and ablation catheters. At baseline, PFO was detected in 43 (21.8%) patients. Clinical and echocardiographic parameters recorded did not differ within patients presenting with or without PFO. Left atrium was accessed via PFO in 39 (90.7% of those with PFO) patients during the first procedure. New-onset IASD occurred in 11 (5.6%) patients following the first procedure and in 1 (2.2%) patient following the second procedure. The clinical and echocardiographic parameters did not differ within the patients irrespective of whether IASD was reported or not. No TS-related complications occurred. In the present cohort, LA access by PFO or single TS for both the mapping and ablation catheters lead to a small risk of asymptomatic IASD, not increased by redo procedures, confirming that it represents a safe approach. No clinical and/or echocardiographic parameters seemed to predict IASD occurrence.

Dabigatran versus warfarin anticoagulation before and after catheter ablation for the treatment of atrial fibrillation

Systemic thromboembolism and bleeding remain the two most common and serious complications of catheter ablation of atrial fibrillation. A variety of periprocedure anticoagulation strategies have been proposed to mitigate these risks. Although operators are now routinely administering dabigatran for anticoagulation in this setting, its relative safety and effectiveness compared to warfarin are unknown. A total of 202 patients received dabigatran as part of their periprocedural anticoagulation regimen at the time of initial or redo catheter ablation for symptomatic atrial fibrillation. A comparison group of 202 patients treated with warfarin was randomly selected from patients undergoing atrial fibrillation (AF) ablation during the same time period. AF types were paroxysmal in 223 patients, persistent in 158 patients, and longstanding persistent in 13 patients. Mean age was 60.0 ± 10.5years, 55% had a history of hypertension, and mean CHADS-VASc score was 1.7 ± 1.3. "Continuous" warfarin or dabigatran was administered in 80 and 32% of patients, respectively. Time to first dose of dabigatran post-procedure was 12.2 ± 10.3h. Two dabigatran and no warfarin-treated patients had systemic thromboembolism (p = NS); five dabigatran and three warfarin-treated patients had bleeding complications (p = NS, combined endpoint p = 0.116). One dabigatran patient had severe pericardial bleeding (3L blood loss). In a retrospective pilot trial comparing the risks of systemic thromboembolism or bleeding complications in patients treated with warfarin or dabigatran anticoagulation, the outcomes were similar. A prospective trial is warranted.

A wider scope on the treatment of atrial fibrillation.

A wider scope on the treatment of atrial fibrillation.

Can Complex Fractionated Atrial Electrogram Recur at the Same Site in Patients with Redo Catheter Ablation of Atrial Fibrillation?

We questioned whether Complex Fractionated Atrial Electrogram (CFAE) can recur at the same site as in first ablation and relate to outcome of the patients underwent redo catheter ablation (re-CA) of atrial fibrillation (AF). METHODS Out of 173 patients undergoing re-CA of AF, 7 patients (3.4%, 60±12 years) in whom automated CFAE (NavX map) guided ablation was performed at the first and re-CA were studied. RESULTS Mean time interval to re-CA was 21±11 months. In 4 of 7 patients (57.1%), no PV reconnection was observed at re-CA. In 6 of 7 patients, LA septum and anterior wall near the LA appendage (LAA) were the most common recurrence sites of CFAE. In 3 patients, AF terminated during ablation of recurrent CFAEs. The CFAE CL became longer (62.5±10.7 ms vs. 88.9±30.7 ms, P=0.06) and % of area of CFAE smaller (3.0±1.3% vs. 0.8±0.9%, P=0.003) than in those at the first ablation. There were no significant differences in LA diameter and LA volume (46.1±8.8 mm vs. 41.9±8.9 mm, P=NS, 144±57.6 cm3 vs. 121±47.2 cm3, P=NS) between two procedures. CONCLUSIONS In re-CA, areas of CFAE became smaller and CFAE CL longer than in those at first ablation. The CFAEs at the septum and peri-LAA were frequently recurred, in which AF terminated during re-CA in 43%.

Insight from Redo Ablation in Patients with Atrial Fibrillation

Background: This study sought to determine the electroanatomical characteristics of recurrent atrial fibrillation (AF) identified during redo catheter ablation (CA) of AF. Methods: Of 1374 patients with CA of AF, 173 consecutive patients (12.6%) underwent redo CA were studied. One hundred forty seven (85.0%) patients underwent a 2nd repeat procedure, and 3rd and 4th and 5th repeat procedure was performed in 20 (11.6%), 5 (2.9%), and 1 (0.5%), respectively. Results: In 173 patients (54±11 years), 90 paroxysmal AF and 83 non paroxysmal AF were identified. The LA volume measured by 3-dimensional CT (106.3±34.7 ml) became significantly smaller than that at first CA (130.6±50.3 ml, P=0.02). In 2nd redo procedure, all PV reconnection was observed in 55 patients (38.2%). PV reconnection as etiology of recurred AF was not common, but its incidence was higher in patients who underwent redo <2 years (29.9% vs. 8.0%, P=0.06). PV stenosis was present in 23 of 173 patients (13.3%), which commonly developed at a single PV (65.2%), and mostly asymptomatic and often occurred in patients with carina ablation. Conclusions: The LA volume was significantly decreased at redo procedure. PV reconnection was not major etiology of recurrent AF, but commonly found in patients underwent redo <2 years. Asymptomatic PV stenosis was not uncommon. The result from redo ablation could guide more effective and safer ablation strategy.

Left Atrial Appendage

Together with pulmonary veins, many extrapulmonary vein areas may be the source of initiation and maintenance of atrial fibrillation. The left atrial appendage (LAA) is an underestimated site of initiation of atrial fibrillation. Here, we report the prevalence of triggers from the LAA and the best strategy for successful ablation. Nine hundred eighty-seven consecutive patients (29% paroxysmal, 71% nonparoxysmal) undergoing redo catheter ablation for atrial fibrillation were enrolled. Two hundred sixty-six patients (27%) showed firing from the LAA and became the study population. In 86 of 987 patients (8.7%; 5 paroxysmal, 81 nonparoxysmal), the LAA was found to be the only source of arrhythmia with no pulmonary veins or other extrapulmonary vein site reconnection. Ablation was performed either with focal lesion (n=56; group 2) or to achieve LAA isolation by placement of the circular catheter at the ostium of the LAA guided by intracardiac echocardiography (167 patients; group 3). In the remaining patients, LAA firing was not ablated (n=43; group 1). At the 12+/-3-month follow-up, 32 patients (74%) in group 1 had recurrence compared with 38 (68%) in group 2 and 25 (15%) in group 3 (P<0.001). The LAA appears to be responsible for arrhythmias in 27% of patients presenting for repeat procedures. Isolation of the LAA could achieve freedom from atrial fibrillation in patients presenting for a repeat procedure when arrhythmias initiating from this structure are demonstrated.

Right Ventricular Septal Versus Right Ventricular Apical Pacing and Subsequent Development of Heart Failure—A Single Centre Experience

roof line was performed only if venous lesion sets were sufficiently close. Patients were cardioverted to SR, if required. Further linear ablation was only performed if SR could not be maintained. Antiarrhythmic drugs were continued if possible. Postprocedure, recurrent persistent atrial tachyarrrhythmias (AT) were cardioverted within 48h of detection. Redo catheter ablation was considered if arrhythmias were detected beyond 3 months. Results: Consecutive patients with persistent (29/47) or permanent (18/47) AF were included. Sixteen patients received a roof line and 1 a mitral isthmus line. 21/47 patients had recurrent early AT with 19/21 requiring cardioversions. At a follow-up time of 339± 160 days 96% (45/47) remain in SR with 66% free of AT including 79% (23/29) persistent and 44% (8/18) permanent. Redo ablations were performed in 1 persistent and 8 permanent patients. Linear ablation did not predict freedom from AT. Early arrhythmias did not predict late recurrence with 10/21 subsequently remaining arrhythmia-free. Conclusions: Pulmonary vein antral electrical isolation with antiarrhythmic drugs and timely cardioversions in the early post-procedural period may promote reverse atrial electrical remodelling in persistent forms of AF. Permanent AF was significantly more likely to require redo ablation. doi:10.1016/j.hlc.2010.06.926

Interatrial Septum Thickness and Difficulty with Transseptal Puncture during Redo Catheter Ablation of Atrial Fibrillation

Patients undergoing catheter ablation for atrial fibrillation (AF) frequently require redo procedures, but there are no data reporting interatrial septum thickness (IAS) and difficulty during repeat transseptal puncture (TSP). Patients undergoing two separate AF ablation procedures had preprocedural fossa ovalis (FO) thickness measured using transesophageal echocardiography (TEE). "Difficult" TSP was defined by two observers as requiring excessive force, or conversion to TEE guidance. The study comprised 42 patients (37 male) with mean+/-SD age 55+/-9 years. Mean FO thickness was significantly greater at the time of redo TSP (2.2+/-1.6 mm vs 2.6+/-1.5 mm at redo, P=0.03); however, this finding was limited to those who underwent initial dual transseptal sheath procedures, FO thickness 2.0+/-1.5 mm and 2.5+/-1.4 mm for TEE 1 and 2, respectively (P=0.048). There was a trend for more frequent difficult redo TSP procedures, 7/42 (17%; 95% confidence interval [CI] 8-31) redo, versus 4/42 (10%; 95% CI 3-23) first TSP. On univariate analysis, FO thickness was not predictive of TSP difficulty; the only predictor of difficult redo TSP was diabetes. IAS thickness at the FO increased following catheter ablation of AF, yet on subgroup analysis this was limited to initial procedures utilizing dual transseptal sheaths. There was a trend toward more frequent difficulty during redo TSP, yet this was not associated with FO thickening. Diabetes may predispose to difficulty during redo TSP; this finding requires confirmation in a larger study population.