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Introduction: Ablation index (AI)-guided radiofrequency ablation has been increasingly used for the treatment of drug-resistant paroxysmal atrial fibrillation (AF)，but the optimal AI targets remain to be determined. We aimed to examine the efficacy and safety of catheter ablation guided by moderate AI values but more strict procedural endpoints in patients with paroxysmal AF., Methods: We conducted a retrospective review of a consecutive series of patients who received their first AI-guided ablation for paroxysmal AF from 2017 to 2018. The standard procedural protocol recommends AI targets as follows: anterior: 400-450; posterior: 280-330; and roof/inferior wall: 380-430. After circumferential pulmonary vein isolation (PVI), we performed bipolar pacing along the ablation line, adenosine triphosphate (ATP)-provocation, and waited for 30 min to verify PVI. The primary clinical outcome was the rate of freedom from AF recurrence at 12 months., Results: A total of 140 consecutive patients were included. The mean procedure and ablation times were 132.2 ± 30.2 min and 24.2 ± 7.9 min, respectively. The first-pass isolation and final isolation rates were documented in 49.3% and in 100% of the patients, respectively. At 12 months, single-procedure freedom from atrial tachyarrhythmias was observed in 92.1% of patients. No major procedure-related complications were encountered., Conclusions: Moderate AI-guided catheter ablation is highly effective for the treatment of drug-refractory paroxysmal AF in real-world settings. Over 90% of patients achieved single-procedure arrhythmia-free survival at 1 year. The outcome was obtained without major complications and the procedure involved relatively short procedure and ablation times., (© 2021 Wiley Periodicals LLC.)

Objectives: Hybrid catheter and surgical ablation has emerged as an effective therapy for patients with persistent atrial fibrillation (AF). The aims of this study were to evaluate the relationship between intraprocedural arrhythmia termination and the long-term outcomes of hybrid ablation in patients with long-standing persistent AF., Methods: From May 2015 through April 2019, 50 patients with persistent AF with a mean duration of 73.3 ± 62.1 (median 54) months underwent single-step hybrid ablation. Pulmonary vein isolation, left atrial posterior wall isolation and left atrial appendage excision or closure were performed through a left-sided thoracoscopic approach. Subsequently, all patients underwent high-density endocardial mapping and electrogram-based ablation with the end point of AF termination., Results: We achieved intraprocedural AF termination in 84% (42/50) patients; this end point was reached in 16 patients during surgical ablation and in 26 patients during catheter ablation. Seven patients underwent repeat catheter ablation. After a mean follow-up period of 29 ± 13 months, the freedom from atrial tachyarrhythmia of a single procedure without the use of antiarrhythmic drugs was 70% (35/50). In the Cox regression model, intraprocedural termination of AF (hazard ratio 0.205, 95% confidence interval 0.058-0.730; P = 0.014) was the sole predictor of success., Conclusions: The 2-year outcomes of a one-stop hybrid ablation with an end point of AF termination are promising in patients with long-standing persistent AF., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Aims: Circumferential pulmonary vein isolation can be effective as sole treatment for persistent atrial fibrillation. However, identifying those patients who will respond to this therapy remains a challenge. We investigated the clinical value of the sequential low-dose ibutilide test for identifying patients with persistent atrial fibrillation in whom pulmonary vein isolation is effective as sole therapy., Methods and Results: In a prospective cohort of 180 consecutive patients with persistent atrial fibrillation, intravenous low-dose (0.004 mg/kg) ibutilide was administered 3 days before ablation and after the completion of circumferential pulmonary vein isolation. In patients in whom ibutilide did not terminate atrial fibrillation pre-procedurally, but successfully terminated it intraprocedurally, no further atrial substrate modification was performed. Pre-procedural low-dose ibutilide failed to terminate the arrhythmia in all patients with persistent atrial fibrillation, while pulmonary vein isolation ± low-dose ibutilide terminated persistent atrial fibrillation in 55 (30.6%) of them (PsAF group 1). The remaining 125 (69.4%) patients underwent electrogram-based ablation (PsAF Group 2). The control group comprised 379 consecutive patients with paroxysmal atrial fibrillation who underwent pulmonary vein isolation over the same period. At 24 months follow-up, 39 (70.9%) patients in PsAF Group 1 and 276 (72.8%) patients in the control group were free from atrial tachyarrhythmias (P = NS); the arrhythmia-free rates in both groups were higher than that in PsAF group 2 (58.4%, P = 0.005)., Conclusion: The sequential low-dose ibutilide test is a simple method for identifying patients with persistent atrial fibrillation in whom pulmonary vein isolation alone is an appropriate treatment strategy., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Introduction: Adenosine triphosphate (ATP)-provoked dormant conduction (DC) and pacing for unexcitability are used to identify conduction gaps along the ablation lines after circumferential pulmonary vein isolation (CPVI). We aim to determine whether ATP provocation and pacing are interchangeable as endpoints for ablation of paroxysmal atrial fibrillation (PAF)., Methods and Results: A total of 107 patients with PAF were randomly divided into two groups after completion of CPVI. In group I (A-P group, n = 53), ATP was administered first. If DC was uncovered, additional ablation was performed until ATP tests were negative. Bipolar pacing along the ablation line was performed subsequently. In group II (P-A group, n = 54), the same protocol was used, but the pacing and the ATP tests were performed in the opposite sequence. The 12-month ablation outcomes of all patients were compared with those of a historical control group of 107 patients with PAF in whom only ATP test was performed. Regardless of which test was performed first, the other modality still identified conduction gaps. In group I, pacing maneuvers identified gaps in 49% (n = 26) of patients who had negative ATP tests. In group II, ATP tests uncovered DC in 18.5% (n = 10) of patients in whom pacing identified no gaps. After 12 months, a higher proportion of patients (91.6%) were free from atrial tachyarrhythmias compared with the historical control group (81.3%; P = 0.031)., Conclusion: Pacing along the ablation lines and ATP provocation are complementary tests for evaluating the durability of CPVI and can lead to better long-term outcomes when used in combination., (© 2019 Wiley Periodicals, Inc.)

Aims: Transient ST-T elevation (STE) is a rare complication that occurs during transseptal catheterization. This study aims to delineate the incidence and characteristics of transient STE during transseptal catheterization for atrial fibrillation (AF) ablation., Methods and Results: Consecutive patients who underwent fluoroscopy-guided transseptal catheterization for circumferential pulmonary vein radiofrequency ablation in Beijing An Zhen Hospital from January 2006 to January 2013 were enrolled in this study. Out of 2965 patients with a total of 3452 transseptal catheterization procedures, 13 patients (0.38%, mean age 57 ± 8, 6 female, 12 paroxysmal AF, mean left atrial diameter 35.4 ± 3.8 mm) had STE. ST-T elevation occurred after transseptal puncture in 10 patients and after pulmonary vein venography in three patients. Systolic blood pressure (129 ± 10 vs. 104 ± 20 mmHg, P < 0.001), diastolic blood pressure (78 ± 6 vs. 64 ± 11 mmHg, P < 0.001), and heart rate (83 ± 19 bpm vs. 64 ± 23 b.p.m., P = 0.022) significantly decreased when STE occurred. Eleven patients complained of chest pain, one patient complained of dizziness, and one patient had no symptoms. Patients recovered in about 4.6 min (2-10 min) with dopamine or fast saline drip. Catheter ablation of AF was completed in all the 13 patients without sequelae or other complications. Four of the 13 patients (30.8%) had recurrence of AF after a mean follow-up of 21.7 months., Conclusion: ST-T elevation is a rare complication associated with transseptal catheterization without sequelae. Catheter ablation of AF could be safely completed in these patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)

Unlabelled: Atrial Remodeling and Lone Atrial Fibrillation., Background: We sought to investigate the role of anatomic remodeling of the atria and pulmonary veins (PVs) in the progression of lone atrial fibrillation (AF) using dual-source computed tomography (DSCT)., Methods and Results: From 1,308 consecutive patients referred for an index ablation procedure for AF, we prospectively enrolled 29 consecutive patients with recently developed (<3 months) lone persistent AF (PsAF) and 23 consecutive patients with short-lasting (6-12 months) lone PsAF, all of whom had a history of paroxysmal AF (PAF). The control group consisted of 33 patients with lone PAF. On DSCT, the recently developed PsAF group showed more extensive atrial anatomic remodeling than the PAF group as shown by ∼40% higher spot biatrial volume, even though the mean duration of continuous AF was only 6 weeks. In contrast, the DSCT variables in the recently developed PsAF group and the short-lasting PsAF group were comparable, despite the fact that the mean duration of continuous AF in the latter group was 8 months. Series of cross-sectional areas of the ostial 1.5 cm of PV trunks were comparable in the PAF and PsAF groups in all but 3 ostial planes. A higher spot left atrial volume was the only independent factor associated with the progression of lone PAF to PsAF (OR: 1.06, 95% CI: 1.03-1.09, P<0.0001) on logistic regression., Conclusions: Prominent anatomic remodeling of the atria, rather than the PVs, underlies the mechanism of recent progression of lone paroxysmal AF to the persistent variety., (© 2012 Wiley Periodicals, Inc.)

Background: Radiofrequency (RF) ablation has become a widely accepted treatment for atrial fibrillation (AF). This study aimed to identify the efficacy and safety of pulmonary vein (PV) ablation with ethanol and to explore an alternative energy source for catheter ablation of AF., Methods: Twelve open-chest mongrel dogs were randomized into ethanol ablation group and control group. Both the injections and electrophysiological mapping procedures were performed epicardialy. In ethanol ablation group (n = 6), injections were performed to circumferentially ablate the root of each PV (0.2 ml each site, 3 mm apart) with 95% ethanol using an 1 ml injector. In control group (n = 6), saline was injected other than ethanol. PV isolation was confirmed with a circular catheter immediately after the procedure and at follow up of 30 days. PV isolation was defined as the absence of PV potentials at each electrode of the circular catheter positioned at the PV side of the lesions, as well as complete conduction block into left atrium (LA) during PV pacing., Results: PV electrical isolation with complete bidirectional conduction block was achieved with ethanol immediately and at 30 days in 95% of PVs, while saline injection caused only transient conduction changes between LA and PVs. In ethanol group, histologic analysis showed transmural lesions at 30 days. And there was no evidence of PV stenosis or thrombus formation. Mean LA diameter was not significantly different between baseline and 30 days., Conclusion: Ethanol is a safe energy source to effectively isolate PV in canine model and may be promising in endocardial ablation procedure of AF patients in the future.

Objective: To investigate the incidence, type, and predictors of asymptomatic relapse of atrial tachy-arrhythmia (ATa) after circumferential pulmonary vein isolation (CPVI) in patients with atrial fibrillation (AF)., Methods: Forty-eight consecutive patients with AF underwent CPVI and were followed up. Forty-eight hours Holter recording was performed 1, 3, and 6 months respectively after the initial CPVI procedure. Predictors of asymptomatic ATa relapse were determined by Logistic regression analysis for eight variables as follows: age, gender, AF type, existence of organic heart disease, diameter of left atria, left ventricular ejection fraction, procedure time, and heart rate variability after the procedure., Results: Complete Holter data were acquired in 42 patients, 26 males and 16 females, aged: 58 +/- 14, including 25 patients with paroxysmal AF and 17 with non-paroxysmal AF. The standard deviations of R-R interval (SDNN) of the non-paroxysmal AF group was 92 ms +/- 19 ms, significantly longer than that of the paroxysmal AF group (78 ms +/- 15 ms, P = 0.011). The incidence of asymptomatic ATa recurrence rates 1, 3 and 6 months after CPVI were 8%, 12%, and 8% respectively in paroxysmal AF group and 23.5%, 29.4%, and 35.3% respectively in the non-paroxysmal AF group. The incidence of asymptomatic ATa recurrence 6 months after CPVI in the non-paroxysmal AF group was significant higher than that in the paroxysmal AF group (P < 0.05). AF was the dominant arrhythmia among the asymptomatic recurrence ATa, while atrial tachycardia constituted the major arrhythmia of the symptomatic recurrent ATa., Conclusion: (1) Asymptomatic ATa relapse is common among the patients undergoing CPVI. (2) The dominant type of asymptomatic recurrent arrhythmia is AF. (3) The independent predictors for asymptomatic ATa recurrence include non-paroxysmal AF, left atrial enlargement, and increase of SDNN.

Atrial fibrillation (AF) is the most common sustained arrhythmia, and treatments with anti-arrhythmia drugs (AADs) have been frustrating. Limitations of AADs prompted the development of percutaneous catheter ablation. In contrast to AADs, percutaneous catheter ablation offers the possibility of a lasting cure. The successful cure of AF by percutaneous catheter ablation comes from a widespread recognize that pulmonary vein antrum (PVA) plays an important role in the genesis and maintenance of AF, and circular ablation along the PVA can eliminate majority of AF. PVA is comprised of pulmonary vein-left atrium junctions. However, during ablation procedure, definition of PVA solely depends on angiography, and it is largely experience-dependent and there is a great deal of variation involved. Our study in patients with AF found that a unique potential with double deflections could be documented along PVA, but it cannot be recorded at PV side or LA side. Thus, we propose that documentation of PVA potentials can be used as a landmark to define PVA. Unlike angiography, documentation of PVA potentials can be objectively carried out by different operators, and the variations due to experience can be avoided.

Objective: To investigate the efficacy and safety of circumferential pulmonary vein (PV) linear ablation (CPVA) guided by 3-D mapping system in patients with chronic atrial fibrillation (CAF)., Methods: From August 2004 to November 2005, 100 consecutive patients with CAF were admitted to undergo CPVA guided by CARTO system and EnSite NavX system, the main procedure end point is electrical isolation of PVs. Success was defined as atrial tachyarrhythmia free without any antiarrhythmia drugs for at least 3 months. Clinical and procedural variables were collected, ANOVA analysis was employed to identify the risk factors predicting recurrence, P < 0.05 was considered significant., Results: After a mean of 9.7 +/- 5.7 months follow up, 70% (70/100) of patients freed from AF. ANOVA analysis identified isthmus ablation and poor left ventricular ejection fraction as the independent factors predicting success. Complications including pericardial tamponade (3 cases, 3%), stroke (1 case, 1%), asymptomatic pulmonary vein stenosis (2 cases, 2%)., Conclusion: CPVA guided by 3-D mapping system can be performed in CAF patients with an acceptable efficacy, but safety need to be improved.

Background: Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear., Methods: From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of < 300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test., Results: Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155 +/- 43) ms (2 PVTs in 2 patients received SPVA, 26 PVTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P = 0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT (P = 0.75)., Conclusions: PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.

Background: Recurrent atrial tachyarrhythmia (ATa) after circumferential pulmonary vein ablation (CPVA) includes atrial tachycardia (AT) and atrial fibrillation (AF). However, whether there are some differences in clinical course and mechanisms between the recurrent AT and the recurrent AF remained unclear. This study was conducted to investigate the incidence, mechanism, clinical course of the recurrent AT and AF in patients under CPVA., Methods: One hundred and thirty consecutive patients (M/F = 95/35) with highly symptomatic and multiple antiarrhythmic drugs (AADs) refractory paroxysmal (n = 91) or persistent (n = 39) AF were included. The ablation protocol consisted solely of two continuous circular lesions around the ipsilateral pulmonary veins (PV) guided by CARTO system. The endpoint of CPVA is PV isolation. For patients with recurrent ATa within 2 months after the initial procedure, cardioversion with direct current was attempted if the ATa lasted for more than 24 hours. A repeat ablation procedure was performed only for patients with AADs refractory recurrent ATa and at least followed up for 2 months after the initial procedure., Results: Within 2 months after the initial procedure, 52 patients (40.0%) had experienced episodes of symptomatic recurrent ATa. Among them, 23 patients (44.2%) with recurred AT alone (AT group), 14 patients (26.9%) with recurred AF alone (AF group), and 15 patients (28.8%) with recurred AT and AF (AT plus AF group). The delayed cure rate (65.2%) in AT group was significant higher than that in AF group (21.4%, P < 0.05) and AF plus AT group (26.7%, P < 0.05). A repeat ablation was performed in 21 patients, including 6 patients with recurrent AT alone, 8 patients with recurrent AF alone, and 7 patients with recurrent AF plus AT. The mean number of PV gaps was 1.2 +/- 0.4 in AT group, which was significantly lower than that in AF group (2.6 +/- 0.7, P < 0.05) and AF plus AT group (2.0 +/- 0.6, P < 0.05). Delayed cure rate and number of PV gaps between AF group and AF plus AT group were comparable (P > 0.05)., Conclusions: Present study indicates that recurrent AT and AF after CPVA have the different clinical course and different electrophysiological findings during repeat procedure as follows: (1) After CPVA, spontaneous resolution of recurrent ATa was mainly found in patients with recurrent AT alone (about two thirds patients). (2) The type of recurrent ATa after CPVA is associated with the number of PV gaps.

Objective: To compare two catheter ablation strategies for pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (PAF)., Methods: Fifty consecutive patients who underwent PV isolation by circumferential PV ablation (CPVA group) were compared with 50 consecutive patients who underwent PV isolation by segmental PV ablation (SPVA group). The enrolled subjects in this retrospective study were patients with frequent attacks (more than 3 times per month) and symptomatic PAF. Procedure-related parameters, safety and clinical outcome within 6 months after procedures for the 2 strategies were analyzed., Results: The characteristics and mean procedure time were comparable between the 2 groups. The mean fluoroscopy time and mean ablation time were 57 min +/- 11 min and 42 min +/- 9 min in the SPVA group and 31 min +/- 8 min and 61 min +/- 13 min in the CPVA group (both P < 0.01), respectively. After the first procedure, symptomatic atrial tachyarrhythmias (ATa) recurred in 24 (48%) of 50 patients who underwent SPVA and 15 (30%) of 50 patients who underwent CPVA within 3 months (P = 0.10). During 6 months of follow-up, 82% of patients with CPVA and 60% of patients with SPVA were free of symptomatic ATa without any antiarrhythmic drugs for at least 3 months (P < 0.05). One patient per each group developed asymptomatic right superior PV stenosis., Conclusion: In patients with PAF, CPVA compares favorably with SPVA, but either of them yields a similar clinical safety.

Objective: To investigate the feasibility and efficacy of treating atrial fibrillation (AF) with circumferential pulmonary vein (PV) linear ablation guided by 3 dimensional mapping system and single circular mapping catheter., Methods: From April 2004 to January 2005, PV isolation with circumferential PV linear ablation guided by CARTO system (in 76 patients) or EnSite-NavX system (in 24 patients) was performed in 100 consecutive patients with significantly symptomatic, drug refractory AF. The procedural end-point was complete electrical isolation of bilateral PV., Results: Up to 200 linear circles were produced around each ipsilateral PVs in all 100 cases, and 95.0% (190/200) of PV isolation rate was achieved with a mean procedure time of 150-365 (240 +/- 65) min and a mean fluoroscopy time of 23-61 (37 +/- 12) min, respectively. Eight cases with recurrent AF (8.0%) underwent second session. Cumulative atrial tachyarrhythmias-free rate was 85.0% (85/100) during a mean follow-up of 5.5-12 (10.2 +/- 5.7) months. Atrial tachyarrhythmias-free rate was 66.0% (66/100), 82.0% (82/100), 87.0% (87/100), 85.0% (85/100), 85.0% (85/100), and 88.6% (70/79) during the follow up at 1 month, 2 months, 3 months, 4 months, 5 months and 6 months, respectively. There were 2 complications (1 tamponade and 1 PV stenosis), which were rehabilitated after conservative treatment., Conclusion: PV isolation with circumferential PV linear ablation guided by 3 dimensional mapping system is safe and effective for treating AF.

Objective: To investigate the influence of persistent rapid atrial pacing on the levels of connexin 43 (Cx43) and type III collagen in pulmonary vein and atrium in a canine model., Methods: Sixteen mongrel dogs were divided into rapid atrial pacing (RAP) group (n = 8) and normal control group (n = 8) randomly. In the RAP group, atrial pacing was performed with a rate of 400 bpm for 10 weeks to establish atrial fibrillation model. The tissues of left superior pulmonary vein (LSPV), left atrial free wall (LAFW) and right atrial appendage (RAA) were collected from each dogs. The levels of Cx43 and type III collagen were measured in each tissue., Results: Ten weeks later, persistent atrial fibrillation was induced in all dogs in RAP group. The level of Cx43 in RAP group was higher than that in normal control group (LSPV: 3370.91 +/- 275.11 vs 1405.82 +/- 90.38, P < 0.05; LAFW: 2448.68 +/- 272.10 vs 1467.12 +/- 147.93, P < 0.05, RAA: 2331.96 +/- 199.61 vs 1288.27 +/- 216.22, P < 0.05). The level of Cx43 in LSPV was higher than that in LAFW and RAA in RAP group, whereas the difference between LAFW and RAA was not significant in RAP group. The quantities of type III collagen in RAP group were higher than those in normal control group (LSPV: 3301.97 +/- 309.70 vs 1404.56 +/- 178.02, P < 0.05; LAFW: 2477.86 +/- 190.43 vs 1479.20 +/- 187.17, P < 0.05; RAA: 2045.92 +/- 139.43 vs 1417.07 +/- 139.43, P < 0.05). The quantities of type III collagen in LSPV was higher than those in LAFW and RAA in RAP group., Conclusions: Persistent rapid atrial pacing could increase the levels of Cx43 and type III collagen in pulmonary vein and atrium in a canine model of atrial fibrillation. The levels of Cx43 and type III collagen in pulmonary vein were higher than those in atrium. This findings indicated that pulmonary vein may be a crucial regions in maintaining atrial fibrillation.