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Background: To identify and understand clinically encountered pitfalls in the assessment of transmitral conduction block using differential coronary sinus and left atrial appendage pacing techniques in patients with left mitral isthmus linear ablation., Methods and Results: All the available assessments of mitral isthmus block were thoroughly reviewed in 271 mitral isthmus ablation procedures undertaken among 236 patients from October 2008 to April 2011. Bidirectional block was established in 186 of 271 (69%) procedures. Careful evaluation of electrograms recorded on the multipolar coronary sinus and ablation catheters was undertaken to identify and understand the characteristics of pitfall, if any. Pitfall was encountered in 55 of 271 (20%) procedures among 51 patients and categorized into 6 types (types 1, 3, 4, and 5 led to spurious diagnosis of block; types 2 and 6 led to erroneous diagnosis of absence of block). There were 14, 10, 17, 2, 15, and 3 (total=61) cases of pitfall types 1 through 6, respectively. Operator recognized 42 of 61 (69%) pitfalls intraprocedurally. Recognition of types 1 and 5 was difficult because of indiscernible electrograms at usual amplifier settings or presence of slow conduction mimicking block., Conclusions: Every fifth assessment of bidirectional block across mitral isthmus linear lesion using differential coronary sinus and left atrial appendage pacing techniques encounters a pitfall, which can lead to erroneous clinical diagnosis of block or absence of block. Recognition of pitfall during the procedure is feasible and necessitates careful distinction of far-field left atrium from the local coronary sinus electrograms besides appropriate adjustments in catheter position and pacing outputs.

Background: Termination of persistent atrial fibrillation (AF) is a valuable ablation endpoint but is difficult to anticipate. We evaluated whether temporal and spatial indices of AF regularization predict intraprocedural AF termination and outcome., Objective: The purpose of this study was to test whether temporospatial organization of AF after pulmonary vein isolation (PVI) predicts whether subsequent stepwise ablation will terminate persistent AF or predict outcome., Methods: In 75 patients with persistent AF, we measured AF cycle length (AFCL), temporal regularity index (TRI, a spectral measure of timing regularity), and spatial regularity index (SRI, cycle-to-cycle variations in spatial vector) between right atrial appendage and proximal and distal coronary sinus before and during stepwise ablation to the endpoint of AF termination., Results: AF termination was achieved in 59 patients (79%) by ablation. AF terminated during PVI in 11 patients, who were excluded from analysis. In the remaining 48 patients, TRI and SRI increased during stepwise ablation, as compared with 16 patients without termination (P<.05). AFCL was prolonged in both groups. From receiver operating characteristics analysis of the first 22 patients (training set), a post-PVI TRI increase predicted AF termination in the latter 42 patients (test set) with a positive predictive value of 96%, negative predictive value of 53%, sensitivity of 71%, and specificity of 91%. Results were similar for SRI. After 36 months, higher arrhythmia-free outcome was observed in patients in whom PVI caused temporospatial regularization in AF., Conclusions: Temporal and spatial regularization of persistent AF after PVI identifies patients in whom stepwise ablation subsequently terminates AF and prevents recurrence., (Published by Elsevier Inc.)

Background: Achievement of complete conduction block across left mitral isthmus (MI) is challenging. Anticipation of perimitral conduction time (PMCT) associated with MI block may expedite this procedure. We evaluated the relationship between the preprocedural variables and the quantum of PMCT in patients with bidirectionally blocked MI., Methods and Results: We reviewed clinical and echocardiographic parameters in 290 consecutive patients with confirmed bidirectional MI block during atrial fibrillation (AF) ablation. PMCT was defined as the temporal delay to the latest of the double potentials on the line of block while pacing posteroseptal to it in the left atrium (LA). LA size and type of AF significantly influenced PMCT in multivariate analysis. A cumulative score based on LA size (0≦45 mm; 1>45 mm) and type of AF (0: paroxysmal; 1=nonparoxysmal) ranged from 0 to 2. PMCT was directly correlated to the cumulative score (0: 169 ms; n=78; 95% confidential interval, 156 to 181); 1: 187 ms; n=103; 95% confidential interval, 178 to 196; 2: 209 ms; n=109; 95% confidential interval, 200 to 217). In 61 patients who underwent AF ablation twice, the difference between 2 PMCT values was <30 ms in 75% patients. Another consecutive 143 patients with and without MI block after at least 15 minutes of radiofrequency application were analyzed. Perimitral conduction delay <130 ms ruled out bidirectional MI block. Perimitral conduction delay >173 ms predicted bidirectional block with an accuracy of 86%., Conclusions: LA size and AF type significantly influence PMCT in patients undergoing successful MI ablation. These parameters can be used to predict the time value associated with MI block, preprocedurally.

Objectives: The present study was designed to investigate the feasibility and efficacy of single ablation catheter for complete circumferential pulmonary vein antrum (PVA) isolation., Background: Complete isolation of pulmonary veins is the mainstay for atrial fibrillation (AF) ablation. This is usually performed under the guidance of a circular catheter., Methods: One hundred and ten consecutive patients with paroxysmal AF were prospectively randomized into two groups: single-catheter approach (group 1) and double-catheter approach (group 2). After performing initial circumferential lesions, residual gaps were mapped and closed with single ablation catheter in group 1 or guided by a circular mapping catheter in group 2 using an electroanatomic mapping system (CARTO XP, Biosense-Webster Inc., Diamond Bar, CA, USA)., Results: Complete bilateral PVA isolation was achieved in 22 of the 110 patients after initial ablation. All residual gaps could be correctly identified by activation mapping using single ablation catheter. The distribution of these residual gaps was asymmetric. In group 1, 25 gaps along the right PVA lesions and 49 gaps along the left PVA lesions were identified. All the residual gaps were closed with single-catheter approach. In group 2, 28 gaps on the right side and 53 gaps on the left side were identified using a circular catheter and closed with further ablations. The procedure data and clinical outcomes between the two groups were comparable., Conclusions: Single ablation catheter technique is feasible and as effective as circular catheter mapping in localizing the residual gaps for PVA isolation during ablation of paroxysmal AF.

Background: Early recurrence of atrial fibrillation (ERAF) after catheter ablation is common and has been thoroughly studied. However, very late recurrence of atrial fibrillation (VLRAF) is rarely researched, and its characteristics have not been determined., Hypothesis: The aim of this study was to investigate the clinical characteristics of VLRAF after circumferential pulmonary vein ablation (CPVA), and to identify the risk factors for VLRAF., Methods: We retrospectively studied 259 consecutive patients with atrial fibrillation (AF) who were referred for CPVA. Clinical variables were investigated and predictors of VLRAF were identified., Results: A total of 249 patients were enrolled in this study. After a mean follow-up of 18.2 +/- 4.4 mo, 14 patients (5.6%) had VLRAF. Patients with VLRAF were more likely than those without recurrence to have ERAF (78.6% versus 17.8%, p = 0.000) and persistent AF (50.0% versus 13.0%, p = 0.000), but were less likely to achieve pulmonary vein (PV) isolation (78.6% versus 97.6%, p = 0.000). Bivariate analysis demonstrated that ERAF (odds ratio [OR] 8.148, 95% confidence interval [CI] 2.197-30.222; p = 0.002), persistent AF (OR 8.853, 95% CI 1.773-16.155; p = 0.003), and lack of PV isolation (OR 7.530, 95% CI 1.792-33.122; p = 0.006) were related to VLRAF. Multivariate logistic regression analysis only identified ERAF as a predictor of VLRAF after CPVA (OR 7.461, 95% CI 1.696-24.836; p = 0.006)., Conclusions: Very late recurrence of AF is uncommon after CPVA. That occurs more commonly in patients with ERAF., (Copyright (c) 2008 Wiley Periodicals, Inc.)

Introduction: Circumferential pulmonary vein ablation (CPVA) with the endpoint of pulmonary vein (PV) isolation has been developed as an effective therapy for atrial fibrillation (AF). This endpoint can be achieved either by closing gaps along circular lines or by segmental PV isolation inside the circular lines after creation of initial CPVA lesions. We investigated whether the clinical outcome depends on the PV isolation approach used during the first-time CPVA procedure., Methods and Results: One hundred consecutive patients (69 male; age, 56.7 +/- 11.6 years) who underwent first-time CPVA for treatment of symptomatic AF were enrolled. PV isolation was randomly achieved either by CPVA alone (aggressive CPVA [A-CPVA] group, n = 50) or by a combination of CPVA with segmental PV ostia ablation (modified CPVA [M-CPVA] group, n = 50). Recurrence of atrial tachyarrhythmias (ATa) within 3 months after the initial procedure occurred in 30 patients (60%) in the M-CPVA group and in only 15 patients (30%) in the A-CPVA group (P < 0.01). ATa relapse after the first 3 months was detected in 21 patients (42%) in the M-CPVA group, compared with 9 patients (18%) in the A-CPVA group (P = 0.01). At 13 +/- 4 months, patients treated by the A-CPVA approach had greater freedom from ATa recurrence than patients who underwent M-CPVA (P = 0.01). The M-CPVA approach was the only independent predictor associated with procedural failure (RR 0.318; 95% CI 0.123-0.821; P = 0.02)., Conclusions: When PV isolation is the endpoint of CPVA, the efficacy of the A-CPVA approach is better than that of M-CPVA.

Background: Atrial tachyarrhythmias (ATa) can recur after continuous circular lesions (CCLs) around the ipsilateral pulmonary veins (PVs) in patients with atrial fibrillation (AF). This study characterizes the electrophysiological findings in patients with and without ATa after complete PV isolation., Methods and Results: Twenty-nine of 100 patients had recurrent ATa after complete PV isolation by use of CCLs during a mean follow-up of approximately 8 months. A repeat procedure was performed in 26 patients with ATa and in 7 volunteers without ATa at 3 to 4 months after CCLs. No recovered PV conduction was demonstrated in the 7 volunteers, whereas recovered PV conduction was found in 21 patients with recurrent ATa (right-sided PVs in 9 patients and left-sided PVs in 16 patients). The interval from the onset of the P wave to the earliest PV spike was 157+/-66 ms in the right-sided PVs and 149+/-45 ms in the left-sided PVs. During the procedure, PV tachycardia activated the atrium and resulted in atrial tachycardia (AT) in 10 patients. All conduction gaps were successfully closed with segmental RF ablation. After PV isolation, macroreentrant AT was induced and ablated in 3 patients. In the 5 patients without PV conduction, focal AT in the left atrial roof in 2 patients and non-PV foci in the left atrium in 1 patient were successfully abolished; in the remaining 2 patients, no ablation was performed because of noninducible arrhythmias. During a mean follow-up of approximately 6 months, 24 patients were free of ATa without antiarrhythmic drugs., Conclusions: In patients with recurrent ATa after CCLs, recovered PV conduction is a dominant finding in approximately 80% of patients and can be successfully eliminated by segmental RF ablation. Also, mapping and ablation of non-PV arrhythmias can improve clinical success.

The article explores the impact of complex fractionated atrial electrograms (CFAE) activation direction and rate on electrogram (EGM) fractionation using left atrial high-density mapping. EGM fractionation was found in a minority of continuous CFAE sites in sinus rhythm (SR) and coronary sinus pacing (CSp) rhythm. Using activation maps in SR and CSp, the authors found that 71% of EGM fractionation was caused by wave collision and 24% was caused by regional slow conduction.