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Aims: Pulsed field ablation (PFA) is an emerging non-thermal ablative modality demonstrating considerable promise for catheter ablation of atrial fibrillation (AF). However, these PFA trials have almost universally included only Caucasian populations, with little data on its effect on other races/ethnicities. The PLEASE-AF trial sought to study the 12-month efficacy and the safety of a multi-electrode hexaspline PFA catheter in treating a predominantly Asian/Chinese population of patients with drug-refractory paroxysmal AF., Methods and Results: Patients underwent pulmonary vein (PV) isolation (PVI) by delivering different pulse intensities at the PV ostium (1800 V) and atrium (2000 V). Acute success was defined as no PV potentials and entrance/exit conduction block of all PVs after a 20-min waiting period. Follow-up at 3, 6, and 12 months included 12-lead electrocardiogram and 24-h Holter examinations. The primary efficacy endpoint was 12-month freedom from any atrial arrhythmias lasting at least 30 s. The cohort included 143 patients from 12 hospitals treated by 28 operators: age 60.2 ± 10.0 years, 65.7% male, Asian/Chinese 100%, and left atrial diameter 36.6 ± 4.9 mm. All PVs (565/565, 100%) were successfully isolated. The total procedure, catheter dwell, total PFA application, and total fluoroscopy times were 123.5 ± 38.8 min, 63.0 ± 30.7 min, 169.7 ± 34.6 s, and 27.3 ± 10.1 min, respectively. The primary endpoint was observed in 124 of 143 patients (86.7%). One patient (0.7%) developed a small pericardial effusion 1-month post-procedure, not requiring intervention., Conclusion: The novel hexaspline PFA catheter demonstrated universal acute PVI with an excellent safety profile and promising 12-month freedom from recurrent atrial arrhythmias in an Asian/Chinese population with paroxysmal AF., Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT05114954., Competing Interests: Conflict of interest: V.Y.R. has served as consultant to and has received equity compensation from Hangzhou Dinova EP Technology Co., Ltd; and unrelated to this manuscript, he serves as a consultant for and has equity in Ablacon, Acutus Medical, Affera-Medtronic, Apama Medical-Boston Scientific, Anumana, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, CardioNXT/AFTx, Circa Scientific, CoRISMA, Corvia Medical, East End Medical, EPD-Philips, EP Frontiers, Epix Therapeutics-Medtronic, EpiEP, Eximo, Farapulse-Boston Scientific, Field Medical, Focused Therapeutics, HRT, Intershunt, Javelin, Kardium, Keystone Heart, LuxMed, Medlumics, Middlepeak, Neutrace, Nuvera-Biosense Webster, Oracle Health, Restore Medical, Sirona Medical, SoundCath, Valcare; unrelated to this work, has served as a consultant for Abbott, AtriAN, Biosense-Webster, BioTel Heart, Biotronik, Boston Scientific, Cairdac, Cardiofocus, Cardionomic, CoreMap, Fire1, Gore & Associates, Impulse Dynamics, Medtronic, Novartis, Philips, and Pulse Biosciences; and has equity in DRS Vascular, Manual Surgical Sciences, Newpace, Nyra Medical, Surecor, and Vizaramed. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: To evaluate the feasibility of using radiolabeled fibroblast activation protein inhibitor (FAPI) PET/CT imaging to assess activated fibroblasts in the atria of individuals with AF and to identify factors contributing to enhanced atrial activity., Methods: We constructed left atrial appendage (LAA) pacing beagle dog AF models (n = 5) and conducted 18 F-FAPI PET/CT imaging at baseline and eight weeks after pacing. Right atrial (RA) specimens were collected from these models. Additionally, 28 AF patients and ten age- and sex-matched healthy volunteers underwent 18 F-FAPI PET/CT imaging., Results: RA of AF beagles showed increased 18 F-FAPI uptake. Among AF patients, 18 out of 28 (64.3%) exhibited enhanced atrial FAPI activity. No atrial 18 F-FAPI uptake was observed in the sham beagle and healthy volunteers. In animal RA specimens, 18 F-FAPI activity correlated positively with FAP mRNA (r = .98, P = .002) and protein (r = .82, P = .03) levels, as well as collagen I mRNA expression (r = .85, P = .02). B-type natriuretic peptide levels were associated with atrial 18 F-FAPI activity (OR = 3.01, P = .046)., Conclusion: This proof-of-concept study suggests that 18 F-FAPI PET/CT imaging may be a feasible method for evaluating activated fibroblasts in the atria of AF patients., (© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.)

Background: Ablation index (AI) is a novel technology of ablation lesion quality to help improve homogeneity of lesion size and continuity. In this study, we aim to evaluate whether AI-guided PVI improves clinical outcomes compared to CF-guided PVI in patients with paroxysmal AF (PAF)., Methods: Patients undergoing first-time radiofrequency ablation for PAF were randomized in a 2:1 ratio to two groups: AI-guided PVI and CF-guided PVI. In the AI group, AI ≥500 was recommended at the anterior/superior/inferior walls, 350-400 at the posterior wall, and inter-lesion distance ≤4 mm. The primary endpoint is the freedom from atrial arrhythmia recurrence during 12 months follow-up, without antiarrhythmic drug therapy (ADT). The key secondary endpoints include intra-procedural efficiency and peri-procedural complications., Results: Two hundred twenty five patients were randomized (AI group [n = 149] and CF group [n = 76]). First-pass isolation rate in AI group was significantly higher than that in CF group (58.3% vs. 43.4%, p = .035). After a median follow-up of 12.2 months, 154/225 (68.4%) of patients were free from atrial arrhythmia recurrence without ADT, which was higher in AI group compared with CF group, but without significant difference (71.1% vs. 63.2%, p = .253). The incidence of peri-procedural complications is low and without difference between two groups., Conclusions: AI-guided ablation provided higher acute efficacy than CF-guided ablation in PV isolation for patients with paroxysmal AF. The long-term success rate in AI group was higher than CF group, but did not reach statistical significance., (© 2022 Wiley Periodicals LLC.)

Background: Benefits of adjunctive ablation strategies beyond circumferential pulmonary vein isolation (CPVI) are uncertain in patients with persistent atrial fibrillation (PeAF)., Objectives: This study sought to compare clinical outcomes of CPVI plus low-voltage area (LVA) modification during STABLE-SR (SubsTrate ABlation in the LEft Atrium during Sinus Rhythm) vs circumferential pulmonary vein isolation (CPVI) alone in patients with PeAF., Methods: From March 2018 to August 2019, 300 patients with PeAF who underwent de novo ablation were recruited and prospectively randomized to either STABLE-SR group (n = 150) or CPVI alone (n = 150) group. In the STABLE-SR group, after CPVI, high-density voltage mapping of left atrium (LA) was performed during sinus rhythm, and additive ablation targeted LVA and complex electrograms, if any were present. All the ablations were titrated by ablation index. The primary endpoint was freedom from documented atrial arrhythmias lasting for ≥30 s without the use of antiarrhythmic drugs, after a single ablation procedure and blanking period of 3 months., Results: After 18 months, atrial-arrhythmia-free survival did not differ significantly between STABLE-SR group and CPVI alone group (67.2% vs 67.4%; HR: 0.89; 95% CI: 0.55-1.36; P = 0.52). Only around one-half of the patients (50.2%) had abnormal LA substrate with a medium LVA burden of 4.6% (2.1%-9.5%). However, the success rate differs dramatically between patients with normal vs abnormal LA substrate (84.8% vs 60.9%; P < 0.001)., Conclusions: Additional LVA ablation did not improve successful rates of CPVI in this PeAF cohort, of whom one-half had normal LA substrate. Voltage map could identify patients with PeAF with normal LA substrate who can achieve excellent rhythm control with CPVI alone. (CPVI Alone Versus CPVI Plus Electrophysiological Substrate Ablation in the LA During SR for the Treatment of Non-PAF [STABLE-SR&#95;II]; NCT03448562)., Competing Interests: Funding Support and Author Disclosures This trial was supported by a research grant (IIS 476) from Biosense Webster. Dr Chen has received lecture fees from Biosense Webster, St. Jude Medical, Medtronic, Bayer, and Boehringer Ingelheim. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: This prospective study explored relevant factors and clinical significance of atrial 18F-fluorodeoxyglucose (FDG) uptake in patients with atrial fibrillation (AF)., Methods and Results: One hundred AF patients underwent baseline FDG imaging prior to radiofrequency catheter ablation (RFCA). Of those, 30 subjects underwent additional FDG imaging at 3 months post-RFCA. Voltage mapping of the left atrium was analysed as a voltage score. Patients who received RFCA were followed for 26 months (17-31 months) to assess recurrence. At baseline FDG imaging, 74% of patients with persistent AF (PsAF) and 24% of patients with paroxysmal AF showed increased atrial FDG uptake. The prevalence was higher in the right atrium (49%) than in the left atrium (15%, P < 0.001) or left atrial appendage (21%, P < 0.001). Multivariate analysis demonstrated that PsAF and elevated B-type natriuretic peptide (BNP) were related to enhanced right atrial (RA) activity, and increased epicardial adipose tissue (EAT) activity was predictive of left atrial (LA) activity. LA activity was inversely associated with voltage score, while increased FDG uptake in the right atrium was predictive of successful AF termination by RFCA. Atrial FDG activities decreased significantly post-RFCA, but none of the FDG parameters were predictive of AF recurrence., Conclusions: Enhanced RA activity was associated with elevated BNP level, whereas LA activity was related to the increased activity of EAT and inversely correlated with LA fibrosis. Increased RA activity was predictive of successful AF termination by RFCA in PsAF patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Background: Thoracoscopic ablation has emerged as an effective therapy for patients with long-standing persistent Atrial fibrillation (LsPAF). We aimed to investigate the immediate electrophysiological characteristics following modified ablation with 3 circular and 3 linear lesions in the thoracoscopic procedure via a unilateral approach., Methods: Between May 2015 and October 2018, 40 patients underwent the one-stage hybrid procedure for LsPAF. Isolation of the pulmonary veins (PV) and left atrium posterior wall (LAPW), excision of the left atrial appendage (LAA), and high-density endocardial mapping and individualized percutaneous catheter ablation for AF termination were performed., Results: The modified thoracoscopic procedure may enable successful PV and LAPW isolation and LAA removal. Endocardial electrophysiological examination showed 6 out of 40 (15%) patients with a right PV gap, 3 (7.5%) patients with incomplete roof lesions, and 8 (20%) patients with incomplete Dallas lesions. A total of 44 driving areas were mapped and ablated. Thirty-five patients achieved procedural AF termination. After a mean follow-up period of 26 months, the success rate of a single procedure was 85%. Cox regression analysis demonstrated that the failure of procedural AF termination may be a risk factor in atrial tachyarrhythmia recurrence., Discussion: Endocardial electrophysiological examination is a necessary partner to thoracoscopic ablation. Our modified thoracoscopic ablation and driving areas-based ablation contribute to high rates of procedural AF termination, which may lead to reduced recurrence rate. The hybrid procedure may be an effective strategy for the management of LsPAF.

Background: Pulmonary vein isolation (PVI) has become the cornerstone of atrial fibrillation (AF) ablation, but long-term success rates remains suboptimal, due in large part to late PV reconnection and insufficient ostial substrate modification., Objective: To evaluate whether ablation index (AI)-guided PVI with electrical isolation and quantified ostial substrate modification improves clinical outcomes when compared with contact force (CF)-guided ablation in patients with paroxysmal atrial fibrillation (PAF)., Methods: The PAF-AI trial (ChiCTR1900022041) is a prospective, multi-center, randomized controlled clinical trial enrolling patients with PAF with an indication for catheter ablation. Patients are randomized into a 2:1 fashion to two treatment arms: AI-guided PVI (n = 151) and CF-guided PVI (n = 75). In the AI-guided PVI group, real-time automated display of radiofrequency applications (Visitag™) is used with AI ≥ 500 recommended at the anterior/superior/inferior walls and 350-400 at the posterior wall. In CF-guided PVI group, the value and direction of CF are displayed, with the lesion dots manually annotated. The primary endpoint is the freedom from AF recurrence at 12 months following ablation, without antiarrhythmic drug. The primary pre-specified secondary endpoints include intraprocedural efficiency and peri-procedural complications., Conclusions: PAF-AI trial compares the effectiveness and safety of two different strategies of PVI in patients with PAF, AI-guided PVI versus more established CF-guided PVI. This prospective, multi-center, randomized controlled trial, with comparative data evaluating procedural and long-term follow-up results, aims to evaluate the impact of AI-guided strategy on AF ablation compared with the current standard of care RF ablation approach.

Background: This retrospective study was designed to explore the factors relevant to increased atrial 18 F-fluorodeoxyglucose (FDG) uptake in patients with atrial fibrillation (AF) who had undergone routine whole-body positron emission tomography/computed tomography (PET/CT) imaging., Methods and Results: Forty-eight consecutive AF patients (32 persistent, 16 paroxysmal) were identified from our routine FDG PET/CT database. Twenty-two control subjects were selected to establish the normal range of FDG uptake (maximum standardized uptake value, SUV max ) in target tissues. A target-to-background ratio (TBR) was calculated to determine abnormal uptake in the atrium and atrial appendage (AA). Univariate comparisons and multivariate regression analyses were conducted to explore the factors associated with the increased FDG accumulation in the atrium and AA. Seventeen AF patients, all with persistent AF, had increased atrial FDG uptake. Most of them (14, or 82.4%) had increased uptake in the right atrium. Eleven AF patients, 9 with persistent AF, had increased uptake in the AA, and bilateral AAs were equally involved. Multivariate logistic regression analyses identified that female gender, persistent AF, and activity in epicardial adipose tissue (EAT) were independent factors predicting the increased activity of the atrium; also, SUV max of the left ventricle was found for the AA. In addition, multivariate linear regression analyses showed that EAT activity was the only independent variable linearly correlated with the activity of the atrium and AA., Conclusions: Atrial uptake was present in persistent AF and localized mainly in the right atrium, whereas bilateral AAs could be equally involved. Multiple factors contributed to the increased activity in atrium; in particular, the EAT activity was independently correlated with the activity of the atrium and AA.

Atrial fibrillation (AF) is the most common type of heart arrhythmia. Currently, the pathogenesis of AF is not fully understood yet. A growing body of evidence highlighted the strong association between inflammation and the pathogenesis of AF. C-reactive protein (CRP) is an inflammation marker with increased expression in AF. Therefore, the aim of this study was to determine if CRP promotes inflammation, which may sequentially mediate the onset of AF and the concurrent atrial fibrosis, through TLR4/NF-κB/TGF-β pathway. HL-1 cells were treated with either 25 or 50 μg/ml recombinant human CRP. TGF-β1 and NF-κB inhibitors were given either solely or together to the 50 μg/ml CRP-treated cells. Cell proliferation, apoptosis, the expression of apoptotic factors and TLR4, IL-6, TGF-β1, Smad2, and the phosphorylation of Smad2 were determined. Data showed that CRP induced dose-dependent inhibition on cell proliferation and promoted cell apoptosis, which was induced through both intrinsic and extrinsic pathways. Such effects were reversed by inhibiting TGF-β1 and/or NF-κB. Inhibition of TGF-β1 and/or NF-κB also reduced the expression of TLR4 and IL-6. Inhibition of NF-κB alone weakened the expression of TGF-β1 and phosphorylation of Smad2. Our study demonstrated that CRP is not only a marker, but also an important mediator in the induction of inflammation and likely the pathogenesis of AF. We for the first time reported CRP-induced activation and cross-talk between TLR4 and NF-κB/TGF-β1 signaling pathway in a cardiomyocyte model. Reducing CRP and targeting TLR4/NF-κB/TGF-β1 pathway may provide new insights in the therapeutic interventions to inflammation-induced AF., (© 2019 The Author(s).)

Atrial remodeling plays a significant role during the progression of atrial fibrillation (AF). Left atrial wall thickness (LAT) is a subjective and easily acquirable indicator referring to structural remodeling. Therefore, we aimed to investigate the association between LAT and atrial remodeling substrate, and to explore the predictive role of LAT about strong maintenance substrate and poor response to catheter ablation.LAT was measured by cardiac computed tomography in 2 selected locations (roof and floor) in 100 persistent AF patients. Then the low-dose-ibutilide-facilitated catheter ablation was performed and atrial maintenance substrate was categorized as weak, mild, and strong, based on the response to circumferential pulmonary vein isolation or complex fractionated atrial electrograms ablation. During follow-up, the success rate was evaluated. LAT showed a progressive thickening tendency from weak, mild, to strong maintenance substrate (roof: 2.2 mm vs. 2.6 mm vs. 3.9 mm, P < .0001; floor: 1.7 mm vs. 2.0 mm vs. 2.5 mm, P < .0001). During follow-up, the success rate of ablation was decreased with the maintenance substrate strengthening (weak 80%, mild 64.53%, strong 31.43%, P = .009). LA roof thickness >3.10 mm might be the predictor to strong atrial maintenance substrate and poor response to ablation.LAT was associated with the remodeling extent of atrial maintenance substrate and might predict the response to catheter ablation. These findings could help the clinicians to select the appropriate ablative strategy and predict the complexity and prognosis before catheter ablation.

Background: Radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) is known to induce left atrial remodeling and prothrombotic response., Aims: This study aimed to evaluate the effect of remote ischemic preconditioning (RIPC) on left atrial remodeling and prothrombotic response induced by RFCA of AF., Methods: Forty-four patients with drug-refractory paroxysmal AF undergoing RFCA were randomized into RIPC (four short episodes of forearm ischemia) and control groups before the procedure. Blood samples were collected before RIPC/sham RIPC, and 24 and 72 hours later after the procedure. The atrial remodeling marker matrix metalloproteinase-9 (MMP-9) and endothelial damage marker von Willebrand factor (vWF) were measured using enzyme-linked immunosorbent assay. Platelet activation was evaluated by flow cytometric measurements of the expression of platelet P-selectin (CD62P) and active glycoprotein IIb/IIIa receptor (PAC-1). The early recurrence of atrial fibrillation (ERAF) in the two groups was observed over the subsequent 3 months., Results: RFCA resulted in a significant increase in MMP-9 and vWF in both the groups, which persisted for 72 hours. However, the expression of CD62P and PAC-1 showed less increase during RFCA in either group. The RIPC group showed a lower increase in MMP-9 and vWF compared with the control group. In contrast, no significant differences were found in the trend of expression of CD62P and PAC-1 during RFCA between the two groups. The AF recurrence in the 3 months after the ablation was significantly lower in the RIPC group than in the control group., Conclusions: RIPC before RFCA for paroxysmal AF significantly reduces the increase in markers of left atrial remodeling and endothelial damage associated with the procedure, and results in a lower ERAF., (© 2018 Wiley Periodicals, Inc.)

We assessed the thromboembolic risks of atrial fibrillation (AF) patients who had undergone radiofrequency ablation (RFA) using the CHADS2-VASc risk scoring system and further investigated the patterns of warfarin use for thromboprophylaxis according to patient thromboembolic risk scores.In this study, we analyzed the stroke risks of patients who had undergone RFA for AF at our hospital between March 2014 and June 2016 using the CHADS2, CHADS2-VASc, and Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly (> 65 years) (HAS-BLED) scoring systems. We retrieved medications, co-morbidities, and initial warfarin dosage data. The primary outcome was the percentage of patients initiated with warfarin therapy for stroke prophylaxis in AF who had a CHADS2-VASc score of 0.Totally, 309 patients were initiated with warfarin therapy for stroke prophylaxis in AF post-RFA. The baseline warfarin dosage was 2.76 ± 0.61 mg. The baseline CHADS2-VASC score was 2.93 ± 1.96 and 40 (12.95%) had a CHADS2-VASC score of 0, 42 (13.6%) had a CHADS2-VASCscore of 1, and 227 (73.5%) had a CHADS2-VASC score ≥2. The baseline CHADS2 score was 2.17 ± 1.55 and 48 (15.5%) had a CHADS2 score of 0, 68 (22.0%) had a CHADS2 score of 1, and 193 (62.5%) had a CHADS2 score ≥2. The baseline HAS-BLED score was 1.25 ± 0.91 and 69 (22.3%) had a HAS-BLED score of 0, 121 (39.2%) had a HAS-BLED score of 1, and 119 (38.5%) had a HAS-BLED score ≥2. Patients aged <65 years or 65 years, male and female patients, patients with or without hypertension, coronary heart disease, or diabetes mellitus, and patients with or without previous stroke/transient ischemic attack differed significantly in stroke risks by CHADS2-VASC, CHADS2, and HAS-BLED scores for stroke risks. Patients with different baseline international normalized ratio differed significantly in CHADS2-VASC scores. Furthermore, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and statins were of statistical significance for stroke risks.The majority of AF patients post-RFAs was of high stroke risk and received warfarin thromboprophylaxis in accordance with national guidelines. Our findings suggest that low and intermediate stroke risk patients should be evaluated for stroke risks and risk factors so that tailored warfarin thromboprophylaxis therapy can be given and inappropriate use of warfarin in AF patients can be avoided., (Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.)

Background: Remote ischemic preconditioning (RIPC) has been suggested to reduce postoperative release of cardiac and inflammatory markers in patients undergoing cardiac surgery. This study aimed to evaluate the effect of RIPC on nonischemic myocardial damage and inflammatory response in patients undergoing radiofrequency catheter ablation for paroxysmal atrial fibrillation (AF)., Methods: Seventy-two patients with drug-refractory paroxysmal AF undergoing radiofrequency catheter ablation were randomized into RIPC or control groups. RIPC (intermittent arm ischemia through four cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff) was performed once daily on 2 consecutive days before the ablation and immediately before ablation. Cardiac troponin-I (cTnI), high-sensitive C-reactive protein (hs-CRP), and interleukin (IL)-6 levels were measured before RIPC/sham RIPC, after the ablation, and 24 and 72h later. The early recurrence of atrial fibrillation (ERAF) in the two groups was observed over the subsequent 3months., Results: Radiofrequency ablation resulted in a significant rise in cTnI, hs-CRP, and IL-6 in both groups, which persisted for 72h. The RIPC group showed a lower increase in cTnI (P<0.001), hs-CRP (P=0.003), and IL-6 (P=0.008) than the control and tended to have a lower risk of ERAF (hazard ratio [HR]=0.77, 95% confidence interval [CI]: 0.32-1.88)., Conclusions: These results show that RIPC before ablation for paroxysmal AF significantly reduces the increase in cTnI, hs-CRP, and IL-6 associated with the procedure and results in a lower risk of ERAF. These findings suggest that RIPC could provide cardioprotection against nonischemic myocardial damage., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: Left atrial diverticulum (LAD) is not rare in patients with atrial fibrillation (AF). Recent reports focused on its morphology however data on its electrophysiological characteristics are lacking. Our study aims to investigate the electrogram and impedance features of LAD., Methods: This study included 24 patients (mean age, 58.5 ± 10.7 years) with LAD undergoing catheter ablation for AF and 24 gender-and-age-matched individuals without LAD as controls. A bipolar LAD electroanatomic map was acquired in sinus rhythm from all study participants. Points were acquired for diverticulum in the LAD group and for corresponding areas in the control group. Electrogram deflections were counted, bipolar voltage and impedance were measured for each point, and average ∆ impedance and highest ∆ impedance were calculated., Results: A total of 234 points were collected in the two groups. In the LAD vs. control group, median (Q1, Q3) of electrogram deflections was 6 (5, 7) and 4 (4, 5) (P<0.0001), respectively, voltage was not significantly different (1.58 ± 0.68 mV vs. 1.28 ± 0.65 mV, P=0.10), and average ∆ impedance was significantly higher in the LAD group (19.5 ± 9.0 Ω vs 3.9 ± 1.7 Ω, P<0.0001). A cut-off value of 9.5 Ω for ∆ impedance predicted LAD with sensitivity, specificity, and positive and negative predictive values of 83.5%, 92.8%, 92.1% and 84.9%, respectively., Conclusions: Electrogram was more fractionated and impedance was higher at LAD than in corresponding areas without LAD, which might help to differentiate LAD during catheter ablation for AF., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: Previous studies have suggested that systematic ablation of ganglionated plexi (GP) could increase the short-term success rate of radiofrequency ablation for atrial fibrillation, but the long-term efficacy of this approach is not fully established., Methods and Results: Twenty-four mongrel dogs were divided into 3 groups: epicardial GP ablation group 1 (n=8), epicardial GP ablation group 2 (n=8), and a sham operation group (n=8). In the 2 epicardial GP ablation groups, the 4 major GP and the ligament of Marshall were systematically ablated. The effective refractory period and inducibility of tachyarrhythmias were measured before and immediately after GP ablation in epicardial GP ablation group 1 and 8 weeks later in the other 2 groups. Tyrosine hydroxylase and choline acetyltransferase expressions were also determined immunohistochemically 8 weeks later in the latter groups. Compared with epicardial GP ablation group 1 and the sham operation group, epicardial GP ablation group 2 had the shortest atrial and ventricular effective refractory period and the highest inducibility of atrial tachyarrhythmias. The inducibility of ventricular tachyarrhythmias among the 3 groups was comparable. The density of tyrosine hydroxylase- and choline acetyltransferase-positive nerves in the atrium was the highest in epicardial GP group 2, whereas there were no significant intergroup differences in the densities of these 2 types of nerves in the ventricle., Conclusions: After 8 weeks of healing, epicardial GP ablation without additional atrial ablation was potentially proarrhythmic, which may be attributable to decreased atrial effective refractory period and hyper-reinnervation involving both sympathetic and parasympathetic nerves., (© 2014 American Heart Association, Inc.)

Objectives: This study sought to evaluate the relationship between fibrosis imaged by delayed-enhancement (DE) magnetic resonance imaging (MRI) and atrial electrograms (Egms) in persistent atrial fibrillation (AF)., Background: Atrial fractionated Egms are strongly related to slow anisotropic conduction. Their relationship to atrial fibrosis has not yet been investigated., Methods: Atrial high-resolution MRI of 18 patients with persistent AF (11 long-lasting persistent AF) was registered with mapping geometry (NavX electro-anatomical system (version 8.0, St. Jude Medical, St. Paul, Minnesota)). DE areas were categorized as dense or patchy, depending on their DE content. Left atrial Egms during AF were acquired using a high-density, 20-pole catheter (514 ± 77 sites/map). Fractionation, organization/regularity, local mean cycle length (CL), and voltage were analyzed with regard to DE., Results: Patients with long-lasting persistent versus persistent AF had larger left atrial (LA) surface area (134 ± 38 cm(2) vs. 98 ± 9 cm(2), p = 0.02), a higher amount of atrial DE (70 ± 16 cm(2) vs. 49 ± 10 cm(2), p = 0.01), more complex fractionated atrial Egm (CFAE) extent (54 ± 16 cm(2) vs. 28 ± 15 cm(2), p = 0.02), and a shorter baseline AF CL (147 ± 10 ms vs. 182 ± 14 ms, p = 0.01). Continuous CFAE (CFEmean [NavX algorithm that quantifies Egm fractionation] <80 ms) occupied 38 ± 19% of total LA surface area. Dense DE was detected at the left posterior left atrium. In contrast, the right posterior left atrium contained predominantly patchy DE. Most CFAE (48 ± 14%) occurred at non-DE LA sites, followed by 41 ± 12% CFAE at patchy DE and 11 ± 6% at dense DE regions (p = 0.005 and p = 0.008, respectively); 19 ± 6% CFAE sites occurred at border zones of dense DE. Egms were less fractionated, with longer CL and lower voltage at dense DE versus non-DE regions: CFEmean: 97 ms versus 76 ms, p < 0.0001; local CL: 153 ms versus 143 ms, p < 0.0001; mean voltage: 0.63 mV versus 0.86 mV, p < 0.0001., Conclusions: Atrial fibrosis as defined by DE MRI is associated with slower and more organized electrical activity but with lower voltage than healthy atrial areas. Ninety percent of continuous CFAE sites occur at non-DE and patchy DE LA sites. These findings are important when choosing the ablation strategy in persistent AF., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

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: Catheter ablation of persistent atrial fibrillation (AF) is associated with longer procedure times and lower long-term success rates than that of paroxysmal AF., Objective: To test the hypothesis that restoration/maintenance of sinus rhythm (SR) preablation would facilitate AF termination and improve outcomes in patients with persistent AF., Methods: We conducted a 2-group cohort study of consecutive patients with persistent AF and SR restored for at least 1 month prior to ablation (SR group; n = 40) and controls matched by age, sex, and AF duration (control group; n = 40). Radiofrequency stepwise catheter ablation was performed in AF for both groups (induced and spontaneous, respectively). Success was defined as freedom from atrial tachyarrhythmia without antiarrhythmic drugs beyond 1 year of follow-up., Results: During the index ablation procedure, AF cycle length was longer in the SR group than in the control group (183 ± 32 ms vs 166 ± 20 ms; P = .06), suggestive of reverse remodeling. In the SR group, AF more frequently terminated during ablation (95.0% vs 77.5%; P <.05) and required less extensive ablation of complex fractionated electrograms (40.0% vs 87.5%; P <.001) and linear lesions (42.5% vs 82.5%; P <.001). Mean procedural (199.8 ± 69.8 minutes vs 283.5 ± 72.3 minutes; P <.001), fluoroscopy (51.0 ± 24.9 minutes vs 96.3 ± 32.1 minutes; P <.001), and radiofrequency energy delivery (47.5 ± 18.9 minutes vs 97.0 ± 30.6 minutes; P <.001) times were shorter in the SR group. Clinical success rates were similar between groups for first (55.0% vs 45.0%; P = .28) and last (80.0% vs 70.0%; P = .28) procedures, during similar follow-up periods (21.1 ± 9.7 months)., Conclusions: Restoration of SR prior to catheter ablation for persistent AF whenever possible decreases the extent of ablation with the same high clinical efficacy., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

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.)

Introduction: We investigated the impact of the mode of left atrial (LA) access via patent foramen ovale (PFO) versus transseptal (TS) puncture on LA linear lesions during atrial fibrillation (AF) ablation., Methods and Results: We investigated 139 (PFO: 25) consecutive patients who underwent mitral isthmus (MI) and/or LA roof linear ablation. Technical endpoint was completeness of linear lesions and duration of radiofrequency (RF) application. During the initial procedure, complete MI and LA roof blocks were created in 13 of 19 (68%) and 14 of 17 (82%) patients in the PFO group, and in 57 of 94 (61%) and 54 of 70 (74%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (11.1 ± 8.9 and 15.1 ± 7.6 minutes, P = 0.11), and LA roof (10.1 ± 3.5 and 8.3 ± 5.0 minutes, P = 0.21) between the 2 groups. Among 28 patients who underwent repeat linear ablation, complete MI and LA roof blocks were created in 3 of 4 (75%) and 0 of 1 (0%) patients in the PFO group, and in 16 of 21 (76%) and 7 of 10 (70%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (15.3 ± 8.3 and 19.5 ± 18.3 minutes, P = 0.71), and LA roof (19.0 and 10.3 ± 5.4 minutes, P = 0.19) between the 2 groups. Clinical outcomes at 12 months were also similar., Conclusion: There were no significant differences in the procedural success rates, durations of RF application, 12-month clinical outcomes, and complication rates of LA linear ablation between the PFO and TS groups. Accessing the LA via a PFO is not an unfavorable approach toward LA linear ablation., (© 2011 Wiley Periodicals, Inc.)

Introduction: Creating complete linear block with point-by-point ablation is challenging in the left atrium (LA). The purpose of this study was to evaluate the efficacy of LA linear ablation using a hexapolar linear multielectrode mapping/ablation catheter., Methods and Results: Seventeen patients (age 57 ± 10, 14 male, 6 paroxysmal AF (PAF)) were studied and underwent linear ablation at the mitral isthmus (MI) and LA roof. Ablation was performed with 90 second, 60 °C applications of duty-cycled bipolar/unipolar radiofrequency in a 1:1 ratio simultaneously at all selected electrode pairs. The result could not be evaluated in 2 patients because AF persisted despite cardioversion. Roof line block was confirmed in 9 of 15 (60%) patients. The mean number of applications and the procedural time with and without block was 5.4 ± 2.4 and 4.5 ± 2.2 applications, and 15 ± 8 and 13 ± 7 minutes. MI block was confirmed in 4 of 15 (27%) patients. The mean number of RF applications with and without block was 5.3 ± 2.2 and 9.9 ± 4.4 applications, and the procedural time was 20 ± 9 and 27 ± 10 minutes, respectively. For patients with underlying persistent AF, power was lower than those with PAF but improved when ablation was performed in sinus rhythm. Char was observed in 2 cases; however, no procedure-related complications were observed., Conclusions: In our initial experience, a linear multielectrode catheter using duty-cycled bipolar and unipolar RF energy was inferior to conventional single point irrigated ablation in achieving LA linear block. However, successful linear block was obtained within a short period of time, when it was achieved., (© 2011 Wiley Periodicals, Inc.)

Background: The remote magnetic navigation system (MNS) has been used with a nonirrigated magnetic catheter for atrial fibrillation (AF) ablation. The objective of this study was to evaluate the feasibility and efficiency of the newly available irrigated tip magnetic catheter for index pulmonary vein isolation (PVI) in patients with paroxysmal AF (PAF)., Methods and Results: Between January 2008 and June 2009, 30 consecutive patients with drug-resistant PAF underwent circular mapping catheter-guided PVI with MNS (MNS group). The outcomes were compared retrospectively with those of a conventional hand-controlled ablation technique during the same period in 44 consecutive patients (manual group). All 4 pulmonary veins were successfully isolated in both groups except in 4 patients in the MNS group. Radiofrequency and procedure duration were higher in the MNS group (60 ± 27 versus 43 ± 16 minutes; P = 0.0019) than in the manual group (246 ± 50 versus 153 ± 51 minutes; P < 0.0001). In the patients who underwent only PVI, total fluoroscopic time also was longer in the MNS group than in the manual group (58 ± 24 versus 40 ± 14 minutes; P = 0.0002). At 12-month follow-up after a single procedure, 69.0% of the patients in MNS group and 61.8% of patients in manual group were free of atrial tachyarrhythmia without antiarrhythmic drugs. There was no significant difference in the atrial tachyarrhythmia-free survival between the 2 groups (P = 0.961). Cardiac tamponade occurred in 1 patient in the manual group., Conclusions: In patients with PAF, MNS-guided PVI with the newly available irrigated tip magnetic catheter backed up with manual ablation whenever required is feasible. However, it requires longer ablation, fluoroscopy, and procedural times than the conventional approach in the early experience stage.

Atrial fibrillation (AF) is the most common heart rhythm problem and a leading cause of morbidity and mortality. Serious complications associated with this disorder include cardioembolic stroke, heart failure, and death. The worldwide prevalence of AF is rapidly increasing owing to aging of the population. Abnormal impulse formation in the pulmonary veins is known to trigger paroxysmal AF and radiofrequency isolation of these veins is recommended in drug-refractory AF. Active pharmacological research is directed towards selectively targeting the culprit venous cells. Persistent AF is more likely to be an atrial disease. Intrinsic and extrinsic stressors are believed to cause electrostructural alterations in the atrial tissue leading to profibrillatory state. Further research will elucidate the role of stressors and help develop biomarkers to guide early management of AF. An ideal therapy for AF aims at prevention of onset and progression of AF and reduction of AF-related symptoms, hospitalization, stroke, and mortality.

Background: The role of ligament of Marshall (LOM) in the mechanism of "vagal" atrial fibrillation (AF) is still unknown., Objective: To investigate the impact of LOM ablation on atrial vulnerability to AF induced by inferior left atrial fat pad (ILAFP) stimulation in dogs., Methods: AF inducibility and atrial effective refractory period (ERP) were elevated before and after LOM ablation in 8 of 14 dogs (the ablation group). Same protocol but without LOM ablation was conducted in the remaining 6 dogs (the control group). The activation patterns of LOM and left pulmonary veins (LPVs) during sustained AF were analyzed. The distribution of epicardial cholinergic nerve fibers between LOM and ILAFP was investigated in the control group., Results: Ablation of LOM significantly attenuated AF inducibility (87.5% vs 33.3%, P < 0.001) and prolonged ERPs of the structures in contiguity with LOM (P < 0.05) in the ablation group. In contrast, there was no significant change in ERPs and AF inducibility in the control group. During sustained AF, fractionated atrial electrograms were more common in the LOM area than the LPVs (84% vs 18% of the analyzed episodes, P < 0.001). In 46.7% of the episodes with identifiable LOM spikes, atrial potentials, and LOM spikes were related in 2:1 or 3:2 pattern during the intermittent organized activity. Acetylcholinesterase staining revealed a close cholinergic nerved relationship between LOM and ILAFP., Conclusions: LOM plays a critical role in maintaining AF induced by stimulation of ILAFP. Ablation of LOM can markedly attenuate AF inducibility in this model., (© 2010 Wiley Periodicals, Inc.)

Objective: The present study aimed to evaluate a new method for validation of complete linear block at the left atrial (LA) roof., Background: Linear lesions at the LA roof have been reported to improve the success rate of catheter ablation of atrial fibrillation (AF)., Methods: Complete linear block at the LA roof was evaluated in 31 patients after complete isolation of pulmonary vein antrum (PVA) using a simple method. We hypothesized that complete linear block of the LA roof could be confirmed during sinus rhythm if (1) a continuous line of double potentials could be recorded at the LA roof, and (2) the activation sequence along the posterior wall changed to caudocranial. The results of this method were compared with standard pacing techniques., Results: Thirty-nine lines were assessed using this method: 8 before and 31 after achievement of complete conduction block. After validation of complete linear block at the LA roof, double potentials with a mean interpotential interval of 60 +/- 13 ms were recorded in 25 patients and electroanatomical mapping of the left atrium showed the activation sequence of posterior wall changed to caudocranial in all 31 patients during sinus rhythm. The sensitivity, specificity, positive and negative predictive values of this method for validating complete linear block were 100%, 88.9%, 96.8%, and 100%, respectively., Conclusion: A corridor of double potentials along the roof line and a caudocranial activation sequence along the posterior wall during sinus rhythm can indicate conduction block at the LA roof after PVA isolation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and is responsible for the highest number of rhythm-related disorders and cardioembolic strokes worldwide. Early management of this condition will lower the risk of AF-associated morbidity and mortality. Targeted drug therapy has an important role in preventing the progression of AF through modification of the substrate. Discovery of the role of pulmonary veins as a trigger has been an important breakthrough, leading to the development of pulmonary vein ablation-an established curative therapy for drug-resistant AF. Identifying the underlying reasons for the abnormal firing of venous cardiomyocytes and the widespread progressive alterations of atrial tissue found in persistent AF are challenges for the future. Novel imaging techniques may help to determine the right time for intervention, provide specific targets for ablation, and judge the efficacy of treatment. If new developments can successfully address these issues, the knowledge acquired as a result will have a vital role in preclinical and early management of AF.

Epicardial potential mapping is an efficient way to visualize the potential distribution on the epicardial surface. We found in our previous study, that the traditional linear interpolation used for the epicardial mapping may cause errors and distortions in reconstruction of the electric activities on the epicardial surface especially during the atrial fibrillation. In this study, we devoted on the implementation of a 3D interpolating method, and verified it in comparison with another interpolating method as well as studying of the mechanism of vagal atrial fibrillation (AF). In case studying, we analyzed the epicardial data from seven canine cardiac models using this method and found the macro-re-entry during the sustainable AF is more likely due to the dispersion of refractoriness in the myocardium and does not demonstrated the focal patterns at the beginning of AF. This indicated that the electrophysiological characteristics of myocardium might have been changed during the paroxysmal atrial fibrillation (PAF)., (2010 Elsevier Ltd. All rights reserved.)

Background: Catheter ablation can restore sinus rhythm in selected patients with atrial fibrillation (AF), but its preventive function for thromboembolic events (TE) is still underdetermined., Methods: We retrospectively studied 520 consecutive patients with AF who were referred for circumferential pulmonary vein ablation. The incidence of late TE was investigated, and the predictors of late TE were identified from analysis of the basic clinical variables of patients with late TE., Results: Eight (1.5%) patients experienced late TE during 28+/-8 months follow-up. When TE occurred, most (6/8, 75%) patients were documented with recurrence episode. The recurrence of AF was more frequent in patients with late TE than patients without late TE (75.0% vs 30.5%, P=0.007). Multivariate logistic regression analysis identified that all risk factors, including all clinical variants prior ablation and the CHADS2 score, were not related to late TE but the presence of recurrence was the only predictor of late TE (odds ratio, 5.542; 95% confidence interval [1.416-45.013], P=0.019)., Conclusions: Our study demonstrates a strong relationship between the recurrence after ablation and TE post-operation and supports the proposal that free of recurrence is an indication for discontinuation of anticoagulation after ablation.

Background: Video-assisted thoracoscopic bilateral pulmonary vein (PV) isolation with left atrial appendage (LAA) excision is a novel surgical treatment for patients who have atrial fibrillation (AF) but no indication for open heart surgery. However, the electrophysiological mechanisms of the recurrent atrial tachyarrhythmias after this procedure are unknown., Methods: Eight consecutive patients with highly symptomatic atrial tachyarrhythmias after failed video-assisted thoracoscopic surgery were included in this study. A predetermined stepwise ablation protocol, aimed at termination of the arrhythmia and isolation of all PVs, was conducted. The conduction across the remnant of the LAA was also evaluated in 4 patients., Results: Three patients had AF, which was converted into AT by complex fractionated atrial electrogram ablation in 2. Eleven sustained ATs in 7 patients were mapped during the procedure. A majority of ATs (10 of 11) were terminated by ablation before PV isolation. In total, 10 PV gaps in 7 patients were identified. All residual PV gaps were distributed exclusively in the roof or the bottom of the PV antrum. The conduction time across the remnant of the LAA was 90.7 +/- 11.5 ms. One patient underwent a repeat successful ablation procedure. After a mean follow-up of 10.1 +/- 5.0 months after the last ablation procedure, 7 of 8 patients were free of clinical atrial tachyarrhythmias recurrence., Conclusion: PV gaps are present, with a characteristic distribution, in the majority of patients who fail this surgical procedure, but these gaps are not responsible for the arrhythmias identified. Instead, most are macro-reentrant, isthmus-dependent arrhythmias related to clamp-associated or LAA excision-associated scars.

Objective: Previous studies have shown that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) could reverse structural and electrical atria remodelling and decrease atrial fibrillation (AF) onset or recurrence. The aim of this retrospective study was to investigate whether ACEIs/ARBs had beneficial effects on ablation outcome of chronic persistent AF., Methods and Results: This study included 139 patients with chronic persistent AF who underwent radiofrequency ablation in our centre. Patients were divided into an ACEIs/ARBs group or a non-ACEIs/ARBs group. During follow-up (14.6 +/- 8.9 months) after AF ablation, AF-free survival in the ACEIs/ARBs group was not significantly different from the non-ACEIs/ARBs group (P = 0.339). Univariate analysis showed that predictors for AF-free survival were AF history (HR, 1.064; 95% CI, 1.021-1.108; P = 0.003) and duration of chronic persistent AF (HR, 1.012; 95% CI, 1.005-1.019; P = 0.001). Multivariate analysis showed that predictors for AF-free survival were AF history (HR, 1.051; 95% CI, 1.004-1.101; P = 0.035) and duration of chronic persistent AF (HR, 1.012; 95% CI, 1.004-1.020; P = 0.004). ACEIs/ARBs therapy was not a predictor for AF-free survival neither in univariate nor multivariate analysis., Conclusion: In this observational study, no effect of ACEIs or ARBs was seen on the AF recurrence after ablation of chronic persistent AF.ACEIs/ARBs did not help to predict a better ablation outcome. Predictors for ablation outcome are AF history and duration of chronic persistent AF.

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.

Introduction: The reliability of delayed cure of early recurrence of atrial fibrillation (ERAF) is still undetermined. Furthermore, the predictors of recurrence after delayed cure of ERAF are less investigated in depth., Aims of the Study: The purpose of this study was to investigate the long-term efficacy of delayed cure of ERAF after catheter ablation of AF and explore the he predictors of recurrence after delayed cure of ERAF., Methods and Results: We prospectively studied 300 consecutive patients with atrial fibrillation (AF) who were referred for circumferential pulmonary vein ablation (CPVA). After a follow-up of 19.2 +/- 4.1months, of the 87 patients with early recurrence of AF 41 achieved delayed cure, 11 of them reoccurred AF subsequently. Univariate analysis showed that persistent AF, absence of pulmonary vein (PV) isolation and external cardioversion were related to reoccurrence after delayed cure. Logistic regression analysis identified only absence of PV isolation as a predictor of recurrent AF after delayed cure., Conclusions: Delayed cure after CPVA is relatively common and its efficacy at long-term follow-up is reasonably consistent. However, in patients without PV isolation, delayed cure is unstable and the risk of late recurrence is increased.

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.)

The percutaneous invention of the catheter tip into heart chambers through an artery or vein is invasive and poses potential risks of infection and damaging blood vessels or normal heart tissue. The anterior aspect of the esophagus is always in direct contact with the posterior wall of the left atrium. A recent study found that high intensity focused ultrasound could create precise defects in different cardiac tissues without damage to the surrounding tissue. So we hypothesize transesophageal high intensity focused ultrasound ablation of left atrium posterior wall is a good noninvasive method for treating atrial fibrillation.

Background: Common ostium of the inferior pulmonary veins (PVs) is a kind of unusual variation in pulmonary venous drainage to the left atrium (LA), whose feature of anatomy, electrophysiology, and catheter ablation is rarely demonstrated, and the consecutive series of research for catheter ablation of atrial fibrillation (AF) in patients with that anomaly have not been reported., Methods: A total of 1,226 patients with drug-refractory AF received magnetic resonance angiography (MRA) or multidetector computed tomography (MDCT) scan before ablation. Electrophysiological mapping was used to detect the focal triggers in paroxysmal AF. Basic catheter ablation strategy was circumferential PV isolation with "tricircle" under the guidance of image integration system: two circles surround two superior PVs, and the other surround the common trunk., Results: LA and PVs reconstruction by image integration system showed a common pulmonary venous ostium of the right and left inferior PVs before ablation in 11 patients (0.9%). This anomaly could be classified into two types: type A without a short common trunk of inferior PVs and type B with a short common trunk. Fifty-seven percent paroxysmal AF was revealed focal triggers in the common ostium. The success rate of that strategy was 90%., Conclusion: Common ostium of inferior PVs could be classified into two types according to the presence of a short common trunk or not. The common ostium was usually an important triggering focus in paroxysmal AF. Catheter ablation strategy of circumferential PV isolation with "tricircle" under the guidance of image integration system would be a good choice.

Atrial fibrillation (AF) is the most commonly occurring arrhythmia in clinical practice, however, the mechanism of atrial fibrillation is not well explained. It has been considered that myocardial fibrosis plays a role in atrial fibrillation. Within the heart, this fibrosis is thought to be mediated by transforming growth factor-beta 1 (TGF-beta 1), a potent stimulator of collagen-producing cardiac fibroblasts. Recent studies indicate that atrial fibrillation is associated with elevated serum concentrations of TGF-beta 1 and C-terminal propeptide of procollagen type I (a marker of collagen type I synthesis). TGF-beta 1 was not only associated with the presence of atrial fibrillation but may also predict patients at increased risk for future development of atrial fibrillation. Why TGF-beta 1 in atrial fibrillation is high is a puzzling problem. We hypothesized that TGF-beta 1 is a possible cause of atrial fibrillation by initiating fibrosis response. Atrial interstitial fibrosis has been seen in patients with CHF and in animal models of pacing-induced heart failure. It was demonstrated that TGF-beta 1 levels were increased in the atria after the development of congestive heart failure in dogs. In a similar study, mice with increased expression of TGF-beta 1 were prone to atrial fibrillation development as a result of raised levels of atrial fibrosis. If the hypothesis is confirmed, administration of TGF-beta 1 monoclonal antibodies may be used to eliminate the etiology. It will be a new target point to treat atrial fibrillation.

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: Stepwise segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) have been developed to treat patients with atrial fibrillation (AF), but the preferable approach for paroxysmal AF (PAF) has not been established., Methods and Results: One hundred and ten patients with symptomatic PAF were randomized into a stepwise SPVI group (n=55) or CPVI group (n=55). Systemic SPVI combined with left atrial linear ablation tailored by inducibility of AF was performed in the stepwise SPVI group. Circumferential linear ablation around the left and right-sided pulmonary veins (PVs) guided by 3-dimensional electroanatomic mapping was performed in the CPVI group. The endpoints of ablation are non-induciblity of AF in the stepwise SPVI group and continuity of circular lesions combined with PV isolation in the CPVI group. After the initial procedures, atrial tachyarrhythmis (ATa) recurred within the first 3 months in 23 of the 55 patients (41.8%) who underwent stepwise SPVI and in 20 of the 55 patients (36.4%) who had CPVI (p=0.69). Repeat procedures were performed in 7 patients from the stepwise SPVI group and 5 from the CPVI group (p=0.76). During the 3-9 months after the last procedure, 46 patients (83.6%) from the CPVI group and 43 (78.2%) from the stepwise SPVI group did not have symptomatic ATa while not taking anti-arrhythmic drugs (p=0.63). Severe subcutaneous hematoma or PV stenosis occurred in 3 patients., Conclusions: The efficacy of stepwise SPVI is comparable to that of CPVI for patients with PAF.

Background: Pulmonary veins (PVs) can be completely isolated with continuous circular lesions (CCLs) around the ipsilateral PVs. However, electrophysiological findings have not been described in detail during ablation of persistent atrial fibrillation (AF)., Methods and Results: Forty patients with symptomatic persistent AF underwent complete isolation of the right-sided and left-sided ipsilateral PVs guided by 3D mapping and double Lasso technique during AF. Irrigated ablation was initially performed in the right-sided CCLs and subsequently in the left-sided CCLs. After complete isolation of both lateral PVs, stable sinus rhythm was achieved after AF termination in 12 patients; AF persisted and required cardioversion in 18 patients. In the remaining 10 patients, AF changed to left macroreentrant atrial tachycardia in 6 and common-type atrial flutter in 4 patients. All atrial tachycardias were successfully terminated during the procedure. Atrial tachyarrhythmias recurred in 15 of 40 patients at a median of 4 days after the initial ablation. A repeat ablation was performed at a median of 35 days after the initial procedure in 14 patients. During the repeat study, recovered PV conduction was found in 13 patients and successfully abolished by focal ablation of the conduction gap of the previous CCLs. After a mean of 8+/-2 months of follow-up, 38 (95%) of the 40 patients were free of AF., Conclusions: In patients with persistent AF, CCLs can result in either AF termination or conversion to macroreentrant atrial tachycardia in 55% of the patients. In addition, recovered PV conduction after the initial procedure is a dominant finding in recurrent atrial tachyarrhythmias and can be successfully abolished.

Aims: Evaluation of the clinical outcome of patients with hypertrophic obstructive cardiomyopathy (HOCM) and paroxysmal atrial fibrillation (AF) treated with complete pulmonary vein (PV) isolation guided by three-dimensional (3-D) electroanatomical (EA) mapping., Methods: Circumferential radiofrequency (RF) ablation and continuous circular lesions (CCLs) around the left and right-sided PVs were performed in 4 highly symptomatic patients (2 males; age 57.5 +/- 8.3 years) with HOCM and anti-arrhythmic drug (AAD) refractory paroxysmal AF. Ablation was guided by 3-D EA mapping combined with conventional circumferential PV mapping. The endpoints of the ablation were defined as: (1) absence of all PV spikes documented with the two Lasso catheters within the ipsilateral PVs; and (2) no recurrence of the PV spikes within all PVs following intravenous administration of adenosine., Results: The ablation endpoints were achieved in all patients. A repeat ablation was performed in one patient due to repetitive atrial tachycardia, 1 month after the initial procedure. During a follow-up of 5.8 +/- 2.7 months, all patients are free of AF recurrence. Short episodes of symptomatic AT were documented after the repeat procedure, and were well controlled with oral amiodarone in the patient. No procedure-related complications were observed., Conclusion: The present study demonstrates that complete isolation of ipsilateral PVs guided by 3-D EA mapping is potentially effective for the treatment of highly symptomatic, drug refractory paroxysmal AF in patients with HOCM.

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.

Aims Pulsed field ablation (PFA) is an emerging non-thermal ablative modality demonstrating considerable promise for catheter ablation of atrial fibrillation (AF). However, these PFA trials have almost universally included only Caucasian populations, with little data on its effect on other races/ethnicities. The PLEASE-AF trial sought to study the 12-month efficacy and the safety of a multi-electrode hexaspline PFA catheter in treating a predominantly Asian/Chinese population of patients with drug-refractory paroxysmal AF. Methods and results Patients underwent pulmonary vein (PV) isolation (PVI) by delivering different pulse intensities at the PV ostium (1800 V) and atrium (2000 V). Acute success was defined as no PV potentials and entrance/exit conduction block of all PVs after a 20-min waiting period. Follow-up at 3, 6, and 12 months included 12-lead electrocardiogram and 24-h Holter examinations. The primary efficacy endpoint was 12-month freedom from any atrial arrhythmias lasting at least 30 s. The cohort included 143 patients from 12 hospitals treated by 28 operators: age 60.2 ± 10.0 years, 65.7% male, Asian/Chinese 100%, and left atrial diameter 36.6 ± 4.9 mm. All PVs (565/565, 100%) were successfully isolated. The total procedure, catheter dwell, total PFA application, and total fluoroscopy times were 123.5 ± 38.8 min, 63.0 ± 30.7 min, 169.7 ± 34.6 s, and 27.3 ± 10.1 min, respectively. The primary endpoint was observed in 124 of 143 patients (86.7%). One patient (0.7%) developed a small pericardial effusion 1-month post-procedure, not requiring intervention. Conclusion The novel hexaspline PFA catheter demonstrated universal acute PVI with an excellent safety profile and promising 12-month freedom from recurrent atrial arrhythmias in an Asian/Chinese population with paroxysmal AF. Clinical trial registration ClinicalTrials.gov Identifier: NCT05114954 [ABSTRACT FROM AUTHOR]

Aims This prospective study explored relevant factors and clinical significance of atrial 18F-fluorodeoxyglucose (FDG) uptake in patients with atrial fibrillation (AF). Methods and results One hundred AF patients underwent baseline FDG imaging prior to radiofrequency catheter ablation (RFCA). Of those, 30 subjects underwent additional FDG imaging at 3 months post-RFCA. Voltage mapping of the left atrium was analysed as a voltage score. Patients who received RFCA were followed for 26 months (17–31 months) to assess recurrence. At baseline FDG imaging, 74% of patients with persistent AF (PsAF) and 24% of patients with paroxysmal AF showed increased atrial FDG uptake. The prevalence was higher in the right atrium (49%) than in the left atrium (15%, P  <   0.001) or left atrial appendage (21%, P  <   0.001). Multivariate analysis demonstrated that PsAF and elevated B-type natriuretic peptide (BNP) were related to enhanced right atrial (RA) activity, and increased epicardial adipose tissue (EAT) activity was predictive of left atrial (LA) activity. LA activity was inversely associated with voltage score, while increased FDG uptake in the right atrium was predictive of successful AF termination by RFCA. Atrial FDG activities decreased significantly post-RFCA, but none of the FDG parameters were predictive of AF recurrence. Conclusions Enhanced RA activity was associated with elevated BNP level, whereas LA activity was related to the increased activity of EAT and inversely correlated with LA fibrosis. Increased RA activity was predictive of successful AF termination by RFCA in PsAF patients. [ABSTRACT FROM AUTHOR]

Background: This retrospective study was designed to explore the factors relevant to increased atrial 18F-fluorodeoxyglucose (FDG) uptake in patients with atrial fibrillation (AF) who had undergone routine whole-body positron emission tomography/computed tomography (PET/CT) imaging. Methods and Results: Forty-eight consecutive AF patients (32 persistent, 16 paroxysmal) were identified from our routine FDG PET/CT database. Twenty-two control subjects were selected to establish the normal range of FDG uptake (maximum standardized uptake value, SUVmax) in target tissues. A target-to-background ratio (TBR) was calculated to determine abnormal uptake in the atrium and atrial appendage (AA). Univariate comparisons and multivariate regression analyses were conducted to explore the factors associated with the increased FDG accumulation in the atrium and AA. Seventeen AF patients, all with persistent AF, had increased atrial FDG uptake. Most of them (14, or 82.4%) had increased uptake in the right atrium. Eleven AF patients, 9 with persistent AF, had increased uptake in the AA, and bilateral AAs were equally involved. Multivariate logistic regression analyses identified that female gender, persistent AF, and activity in epicardial adipose tissue (EAT) were independent factors predicting the increased activity of the atrium; also, SUVmax of the left ventricle was found for the AA. In addition, multivariate linear regression analyses showed that EAT activity was the only independent variable linearly correlated with the activity of the atrium and AA. Conclusions: Atrial uptake was present in persistent AF and localized mainly in the right atrium, whereas bilateral AAs could be equally involved. Multiple factors contributed to the increased activity in atrium; in particular, the EAT activity was independently correlated with the activity of the atrium and AA. [ABSTRACT FROM AUTHOR]