Radiofrequency ablation of atrial fibrillation: A 14 years' experience at a tertiary care center in Thailand.

BACKGROUND: The result of atrial fibrillation (AF) ablation varies across centers. Most data are derived from the Western world, while data from Southeast Asian countries are lacking. We aimed to investigate the outcomes of AF ablation in Thailand. METHOD: We performed a retrospective analysis of patients who underwent AF ablation in a tertiary care center, between the years 2006-2020. Details of AF ablation, including pulmonary vein isolation (PVI), and complex fractionated atrial electrogram (CFAE) ablation, were classified. The success rate of AF ablation is determined by freedom from AF beyond 3 months blanking period. Combined success rate of AF ablation was reported along with the success rate of each technique (PVI, CFAE, and combine PVI plus CFAE). RESULT: We identified a total of 171 patients who underwent the first AF ablation. Ninety-four (55%) patients went through PVI, 55 (32%) patients for CFAE ablation, and 22 (13%) patients for PVI plus CFAE ablation. Overall freedom from AF was 73% at 12 months, 66% at 24 months, and 55% at 36 months. The success rate of PVI was 79% at 12 months, 74% at 24 months, and 59% at 36 months. The success rate of CFAE ablation was 63% at 12 months, 51% at 24 months, and 47% at 36 months. CONCLUSION: Catheter ablation of AF is proven safe and effective in Thai population.

Regions of Highly Recurrent Electrogram Morphology With Low Cycle Length Reflect Substrate for Atrial Fibrillation.

Traditional anatomically guided ablation and attempts to perform electrogram-guided atrial fibrillation (AF) ablation (CFAE, DF, and FIRM) have not been shown to be sufficient treatment for persistent AF. Using biatrial high-density electrophysiologic mapping in a canine rapid atrial pacing model of AF, we systematically investigated the relationship of electrogram morphology recurrence (EMR) (Rec% and CLR) with established AF electrogram parameters and tissue characteristics. Rec% correlates with stability of rotational activity and with the spatial distribution of parasympathetic nerve fibers. These results have indicated that EMR may therefore be a viable therapeutic target in persistent AF.

Practical Considerations for the Application of Nonlinear Indices Characterizing the Atrial Substrate in Atrial Fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and in response to increasing clinical demand, a variety of signals and indices have been utilized for its analysis, which include complex fractionated atrial electrograms (CFAEs). New methodologies have been developed to characterize the atrial substrate, along with straightforward classification models to discriminate between paroxysmal and persistent AF (ParAF vs. PerAF). Yet, most previous works have missed the mark for the assessment of CFAE signal quality, as well as for studying their stability over time and between different recording locations. As a consequence, an atrial substrate assessment may be unreliable or inaccurate. The objectives of this work are, on the one hand, to make use of a reduced set of nonlinear indices that have been applied to CFAEs recorded from ParAF and PerAF patients to assess intra-recording and intra-patient stability and, on the other hand, to generate a simple classification model to discriminate between them. The dominant frequency (DF), AF cycle length, sample entropy (SE), and determinism (DET) of the Recurrence Quantification Analysis are the analyzed indices, along with the coefficient of variation (CV) which is utilized to indicate the corresponding alterations. The analysis of the intra-recording stability revealed that discarding noisy or artifacted CFAE segments provoked a significant variation in the CV(%) in any segment length for the DET and SE, with deeper decreases for longer segments. The intra-patient stability provided large variations in the CV(%) for the DET and even larger for the SE at any segment length. To discern ParAF versus PerAF, correlation matrix filters and Random Forests were employed, respectively, to remove redundant information and to rank the variables by relevance, while coarse tree models were built, optimally combining high-ranked indices, and tested with leave-one-out cross-validation. The best classification performance combined the SE and DF, with an accuracy (Acc) of 88.3%, to discriminate ParAF versus PerAF, while the highest single Acc was provided by the DET, reaching 82.2%. This work has demonstrated that due to the high variability of CFAEs data averaging from one recording place or among different recording places, as is traditionally made, it may lead to an unfair oversimplification of the CFAE-based atrial substrate characterization. Furthermore, a careful selection of reduced sets of features input to simple classification models is helpful to accurately discern the CFAEs of ParAF versus PerAF.

Efficacy and Safety of Adjunctive Substrate Modification During Pulmonary Vein Isolation for Atrial Fibrillation: A Meta-Analysis.

BACKGROUND: The efficacy and safety of adjuvant substrate modification (SM; either linear ablation [LA] or complex fractionated atrial electrogram [CFAE] ablation) in addition to pulmonary vein isolation (PVI) for the treatment of symptomatic, drug-refractory atrial fibrillation (AF), have still not been clarified and need further assessment. METHOD: We systematically searched the PubMed, MEDLINE, and Cochrane databases for studies comparing PVI with adjunctive SM versus PVI alone for treatment of drug-refractory AF. RESULTS: Twenty-six (26) studies including 3,409 patients (1,975 PVI + SM; 1,434 PVI alone) were included for further analysis. Atrial fibrillation/atrial tachycardia-free survival of patients with PVI + SM was comparable with that of PVI alone (relative risk [RR], 1.06; 95% confidence interval [CI], 0.98-1.14; p = 0.143). In line with this, the primary clinical outcomes were robust, irrespective of additional LA (RR, 1.07; 95% CI, 0.97-1.18; p = 0.194) or CFAE ablation (RR, 1.04; 95% CI, 0.93-1.16; p = 0.534). Adjuvant SM is associated with longer procedural time (weighted mean difference, 20.72; 95% CI, 10.25-31.20; p = 0.0) and fluoroscopy time (weighted mean difference, 6.66; 95% CI, 1.74-11.58; p = 0.000); surprisingly, it presented similar procedure-related complications as PVI alone during AF catheter ablation (RR, 1.01; 95% CI, 0.68-1.50; p = 0.946). CONCLUSIONS: Adjuvant LA or CFAE ablation do not provide incremental benefit over PVI alone. Although substrate-based ablation markedly prolonged procedural and fluoroscopic duration, there was no evidence of increased risk of procedure-related complications.

Left atrial posterior wall isolation affects complex fractionated atrial electrograms in persistent atrial fibrillation.

BACKGROUND: The impact of left atrial posterior wall isolation (LAPWI) on the complex fractionated atrial electrogram (CFAE) is unknown. METHODS: CFAE mapping was performed before and after LAPWI in 46 patients with persistent atrial fibrillation (AF). RESULTS: LAPWI decreased both the variable (fractionated index ≤ 120 ms; from 60 ± 4 cm2 to 50 ± 4 cm2, P < 0.001) and continuous (fractionated index ≤ 50 ms; from 4.2 ± 1.0 cm2 to 3.5 ± 0.9 cm2, P = 0.036) CFAE areas. Especially, the CFAE areas on the bottom and roof walls of the left atrium and on the posterior and bottom walls of the right atrium significantly decreased after LAPWI. The distribution of variable CFAE areas was not different between the AF-recurrence (n = 9) and AF-free (n = 37) groups before LAPWI; however, it was larger in the anterior and septal walls of the right atrium in the AF-recurrence group than in the AF-free group after LAPWI (anterior wall, 8% ± 2% vs 5% ± 1%, P = 0.048; septal wall, 23% ± 4% vs 16% ± 1%, P = 0.043). The distribution of continuous CFAE areas on the bottom wall of the right atrium was larger in the AF-recurrence group than in the AF-free group both before LAPWI (30% ± 20% vs 4% ± 2%, P = 0.008) and after LAPWI (25% ± 25% vs 3% ± 1%, P = 0.027). CONCLUSIONS: LAPWI decreased the CFAE areas and affected their distribution, which contributed to AF recurrence.

New tailored approach using a revised assessment of fragmented potentials for persistent atrial fibrillation: Early area defragmentation by modified CFAE module.

INTRODUCTION: Pulmonary vein isolation (PVI) is widely performed for atrial fibrillation (AFib). However, it is insufficient to maintain sinus rhythm (SR) in persistent and long persistent atrial fibrillation (Per-AFib). Ablation of complex fractionated atrial electrograms (CFAEs) is currently classified as class IIb, However, the concept of length of potential was different between the current CFAE module of CARTO system and the definition of CFAE potential. The current CFAE module was configured in the shortest complex interval (SCI) mode, in which the meaning of length of potential was the interval of each component of fragmented potentials. That was a part of the potential. On the other hand, the meaning of the definition of CFAE potential was the length of fragmented potential itself. The purpose of this study was to essentially evaluate fragmented potentials by revisiting in interval confidence level (ICL) mode and express them on the map and prospectively investigate the efficacy and prognosis of a new tailored approach for defragmentation, which is called early area defragmentation (EADF). METHODS AND RESULTS: We acquired atrial potentials by modified CFAE module in ICL mode (K-CFAE potential) and visualized the distribution of K-CFAE potential (K-CFAE map). We performed PVI, and we ablated the fragmented areas based on the K-CFAE map. We enrolled 77 patients in this study (control group: 84 patients). After 24-month follow-up, 75.3% were able to maintain SR. CONCLUSIONS: K-CFAE mapping faithfully represented the distribution of fragmented areas. PVI, together with our new tailored approach, EADF, was successful in treating Per-AFib.

Comparison between linear and focal ablation of complex fractionated atrial electrograms in patients with non-paroxysmal atrial fibrillation: a prospective randomized trial.

AIMS: Findings regarding efficacy of substrate modification for non-paroxysmal atrial fibrillation (AF) are inconsistent. We prospectively compared clinical outcomes of complex fractionated atrial electrogram (CFAE)-guided focal ablation (CFA) and CFAE-guided linear ablation (CLA) in patients with non-paroxysmal AF. METHODS AND RESULTS: We randomized 150 patients with non-paroxysmal AF into CFA and CLA groups in a 1:1 ratio. Complex fractionated atrial electrogram distribution was evaluated using an automated algorithm of a three-dimensional mapping system. After pulmonary vein isolation (PVI), CFAE-guided ablation was performed in the left atrium and then in the right atrium (RA). When compared with conventional CFA, CLA was performed based on conventional lines, with additional lines. Atrial fibrillation was not induced after PVI alone or with cavotricuspid isthmus ablation in 20.7% of patients. To achieve the endpoint, additional CFAE-guided RA ablation was required in 42.7% and 36.0% of patients undergoing CFA and CLA, respectively (P = 0.403). Atrial fibrillation was terminated during CFAE-guided ablation in 72.9% and 75.0% of patients undergoing CFA and CLA, respectively (P = 0.792). Termination of atrial tachycardia (AT) or non-inducibility of AF/AT was achieved in 61.3% and 68.0% of patients undergoing CFA and CLA, respectively (P = 0.393). The CLA group showed decreased 1-year freedom from AF/AT recurrence (60.0%, CFA vs. 47.3%, CLA; log rank P = 0.085), but no significant difference throughout the follow-up (22.2 ± 21.0 months) (67.1%, CFA vs. 68.9%, CLA; log rank P = 0.298). CONCLUSION: Long-term efficacy of CFAE-guided ablation was unaffected by the ablation technique in patients with non-paroxysmal AF.

Efficacy of Complex Fractionated Atrial Electrogram-Guided Extensive Encircling Pulmonary Vein Isolation for Persistent Atrial Fibrillation.

Background: In persistent AF, the effect of adjunctive ablation in addition to PV isolation (PVI) is controversial. We considered a new modified PVI including complex fractionated atrial electrogram (CFAE) area. Methods and Results: In 57 patients with persistent AF undergoing first ablation, CFAE were mapped before ablation and CFAE-guided extensive encircling PVI (CFAE-guided EEPVI) was performed. The PVI line was designed to include the CFAE area near PV or to cross the minimum cycle length points of the CFAE area near PV (CFAE-guided EEPVI group). The outcome was compared with conventional PVI in 34 patients with persistent AF (conventional PVI group). During a mean follow-up of 365±230 days after the first procedure, AF in 13 and atrial tachycardia (AT) in 9 patients recurred in the CFAE-guided EEPVI group, while only AF in 17 patients recurred in the conventional PVI group. Eight of 9 AT in the CFAE-guided EEPVI group were successfully ablated at second procedure. After first and second procedures, the recurrence of atrial tachyarrhythmia in the CFAE-guided EEPVI group was significantly reduced compared with the conventional PVI group (8 patients, 14% vs. 11 patients, 32%, respectively; P<0.01, log-rank test). Conclusions: CFAE-guided EEPVI was more effective for persistent AF compared with conventional PVI after first and second procedures, because recurring AT as well as re-conduction of PV was successfully ablated.

Clinical Utility of Intravenous Nifekalant Injection during Radiofrequency catheter Ablation for Persistent Atrial Fibrillation.

BACKGROUND: Radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (AF) is still challenging even in RFCA-era for AF. The aim of this study was to assess the clinical utility of nifekalant, a pure potassium channel blocker,during RFCA for persistent AF. METHODS AND RESULTS: We retrospectively enrolled 157 consecutive persistentAF patientsundergoing first RFCA procedure withcomplex fractionated atrial electrogram (CFAE)ablation after pulmonary veins isolation and compared outcomes between patientswith (NFK group: N=79) and without (No-NFK group: N=78)additional CFAE ablation using intravenous nifekalant (0.3mg/kg). Primary endpoint was 24-month atrial arrhythmia-free survival post ablation.The prevalence of AF terminationwas significantly higher in NFK group than No-NFK group (64.6% versus 7.7%, P<0.001). Arrhythmia-free survival, however, was not significantly different between 2 groups (61.5% versus 54.1%, P=0.63).There was no significant difference between 2 groups in the prevalence of recurrent atrial tachycardia(25.0% versus 23.5%, P=0.89). Arrhythmia-free survivalin patients with AF termination during procedure was significantly higher thanthose without (73.0% versus 41.0%, P=0.002; adjusted hazard ratio 0.48, 95% confidence interval 0.17-0.84, P=0.02) amongNFK group,but not amongNo-NFK group (66.7% versus 53.2%, P=0.53). CONCLUSIONS: Intravenous nifekalant injection during additional CFAE ablation did not improve sinus maintenancerate after RFCA procedure for AF, but AF termination by nifekalant injection could be a clinical predictor of better success rates after procedure.

Influence of substrate modification in catheter ablation of atrial fibrillation on the incidence of acute complications: Analysis of 10 795 procedures in J-CARAF Study 2011-2016.

BACKGROUND AND PURPOSE: In expectation of better outcome of catheter ablation of atrial fibrillation (AF), several strategies of extra-PV (pulmonary vein) substrate modification have been utilized. We assessed whether substrate modification or ablation of extra-PV source is a predictor of complications. METHODS: Japanese Heart Rhythm Society requested electrophysiology centers to register the data of patients who underwent AF ablation. RESULTS: The data of 10 795 AF ablation cases (age; 63.8 ± 10.6 years) treated during 2011-2016 were registered. Pericardial effusion (n = 105), massive bleeding (n = 108), stroke (n = 6), atrial-esophageal fistula (n = 2), and other 114 complications occurred in 323 patients (3.0%). Univariate analysis revealed that age â‰§ 65 years, female gender, heart failure, CHA2DS2-VASc≧3, hemodialysis, deep sedation, and complex fractionated atrial electrogram (CFAE)-guided ablation ([+] vs [-] = 4.3% vs 2.8%, P = .005) were related with the higher incidence of complications. Redo session, 3-D imaging system ([+] vs [-]: 4.4% vs 2.9%, P = .017), and periprocedural dabigatran were related with the lower incidence of complications. None of the linear ablation of the left atrium, ganglionated plexi ablation, and superior vena cava ablation affected the incidence of complications. Multiple logistic regression analysis showed that in addition to 3-D imaging system, age â‰§ 65 years, redo session, and deep sedation, CFAE ablation was an independent predictor of the risk of complications (OR 1.78, P = .001). Specifically, implantation of a permanent pacemaker due to emerging sinus node dysfunction was frequent after CFAE ablation (CFAE [+] vs [-] = 4/1047 vs 2/9748, P < .001). CONCLUSIONS: Among extra-PV ablation strategies, CFAE-guided ablation is a predictor of ablation-related complications.

Clinical Factors Relevant to the Recurrence of Atrial Tachyarrhythmia after Extensive Defragmentation Followed by Thoracic Vein Isolation.

INTRODUCTION: The efficacy of thoracic vein isolation (TVI), an approach to trigger atrial fibrillation (AF), for the management of AF has been established. Our goal was to identify the predictors for late recurrence of atrial tachyarrhythmias (ATAs), for which the patients and procedural and/or echocardiographic parameters were retrospectively analyzed. Although substrate modification in the atrium for the treatment of AF ablation remains controversial, the background associated with the outcome has not been fully investigated. We retrospectively studied 33 patients with paroxysmal AF and 21 with persistent AF undergoing defragmentation followed by TVI. We evaluated the late/early recurrences, defined as ATA at 3 months after/within the single procedure. METHODS AND RESULTS: During a median follow-up period of 22 (11-37) months, 28 patients (52%) experienced a late recurrence. There was a higher incidence of late recurrences in the patients with disease durations of ≥12.4 months, which was the optimal cut-off point measured in the receiver operating characteristic curve analysis, or in those with left atrial diameter >50 mm or with earlier recurrences than the others (19% versus 72%, p=0.01; 0% versus 37%, p=0.02; or 13% versus 53%, p<0.0001 by the log-rank test, respectively). Moreover, there was a trend toward a higher atrial tachycardia (AT)-free rate in the patients with AF termination during the procedure (75% versus 54%, p=0.07 by the log-rank test). A multivariate analysis based on the Cox proportional hazard model showed that disease duration ≥12.4 months or early recurrence was highly associated with the outcomes (HR 3.72, 95%CI 1.42-12.79, p<0.006; HR 4.80, 95%CI 2.24-10.56, p<0.0001). CONCLUSION: The AF duration and early ATA recurrence are the peri-procedural factors significantly relevant to the outcome after extensive defragmentation followed by TVI.

Optimal endpoint for catheter ablation of longstanding persistent atrial fibrillation: A randomized clinical trial.

BACKGROUND: In longstanding persistent atrial fibrillation (LPeAF), the ideal endpoint of ablation remains to be determined. This study was to explore the value of pursuing AF termination or no with the same strategy during ablation on the long-term outcomes in patients with LPeAF. METHODS: Utilized "CCL" strategy is a fixed ablation approach consisting of circumferential pulmonary vein antrum isolation, ablation of complex fractionated atrial electrogram, and linear ablation between two anatomical structures (the mitral isthmus, left atrial roof). Note that 400 patients were randomized to group A (technical endpoint) and group B (pursuing AF termination). RESULTS: A group with technical endpoint had lower rate of acute AF termination (AF→sinus rhythm, 3.5% vs 18.1%; AF→atrial tachycardia, 23.7% vs 44.7%; P < 0.01) and shorter duration of ablation (164.9 ± 20.8 vs 223.4 ± 24.9, P < 0.01), radiofrequency delivery time (69.8 ± 18.1 vs 102.2 ± 26.3, P < 0.01), and x-ray exposure time (18.2 ± 8.8 vs 27.9 ± 12.4, P < 0.01) than those in B group (pursuing AF termination). During follow-up, freedom from atrial arrhythmias did not differ between the two groups after a single ablation procedure (46.5% vs 54.3%, P=0.12) and the final ablation procedure (60.1% vs 65.8%, P  =  0.24). CONCLUSION: In patients of LPeAF, pursuing AF termination during ablation was associated with similar long-term clinical outcome compared to that with technical endpoint. Ablation to termination is not the best strategy during ablation.

Complex fractionated atrial electrograms, high dominant frequency regions, and left atrial voltages during sinus rhythm and atrial fibrillation.

BACKGROUND: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant frequency (DF) sites is generally effective for persistent atrial fibrillation (AF). CFAEs and/or high DF sites may exist in low-voltage regions, which theoretically represent abnormal substrates. However, whether CFAEs or high DF sites reflect low voltage substrates during sinus rhythm (SR) is unknown. METHODS: Sixteen patients with AF (8 with paroxysmal AF; 8, persistent AF) underwent high-density mapping of the left atrium (LA) with a 3-dimensional electroanatomic mapping system before ablation. The LA was divided into 7 segments and the mean bipolar voltage recorded during AF and SR, CFAEs (cycle lengths of 50-120 ms), and DF sites were assessed in each segment with either a duo-decapolar ring catheter (n=10) or a 64-pole basket catheter (n=6). Low-voltage areas were defined as those of <0.5 mV during AF and <1.0 mV during SR. RESULTS: Regional mean voltage recorded from the basket catheter showed good correlation between AF and SR (r=0.60, p<0.01); however, the % low-voltage area in the LA recorded from the ring catheter showed weak correlation (r=0.34, p=0.05). Mean voltage was lower during AF than during SR (1.0 mV [IQR, 0.5-1.4] vs. 2.6 mV [IQR, 1.8-3.6], p<0.01). The regional and overall % low-voltage area of the LA was greater during AF than during SR (20% vs. 11%, p=0.05). CFAEs and high DF sites (>8 Hz) did not correlate with % low-voltage sites during SR; however, CFAEs sites were located in high-voltage regions during AF and high DF sites were located in low voltage regions during AF. CONCLUSIONS: CFAEs and high DF areas during AF do not reflect damaged atrial myocardium as shown by the SR voltage. However, CFAEs and high DF sites may demonstrate different electrophysiologic properties because of different voltage amplitude during AF.

Evaluation of the characteristics of rotational activation at high-dominant frequency and complex fractionated atrial electrogram sites during atrial fibrillation.

BACKGROUND: High-dominant frequency (DF) and continuous complex fractionated atrial electrogram (CFAE) sites as surrogates for localized sources maintaining atrial fibrillation (AF) are potential AF ablation targets. This study aimed to evaluate the characteristics of a rotational activation at high-DF and continuous CFAE sites in AF patients. METHODS: Thirty-two consecutive AF patients (5 paroxysmal and 27 non-paroxysmal) underwent ablation using the NavX system. When AF continued after circumferential pulmonary vein isolation (PVI), high-DF sites of ≥8 Hz and continuous CFAE sites (fractionated intervals ≤50 ms) in the left (LA) and right (RA) atria were recorded using a high-density 20-pole circular mapping catheter for 5 s and ablated. RESULTS: The atrial electrogram characteristics during AF were assessed. A total of 2383 AF beats from 89 high-DF and 19 continuous CFAE sites were investigated. A rotational activation of high-DF and continuous CFAE sites was also observed at 4% and 3% of LA, and 4% and 4% of RA sites, respectively. However, rotational activation was identified in 29 (91%) of 32 patients (mean 3.0±2.6 beats per patient, 80% in the LA). Procedural endpoints were achieved in 26 (81%) of 32 patients: AF termination (n=2) and AF cycle length slowing of >10% (n=26). CONCLUSIONS: Rotational activation could be identified in high-DF and continuous CFAE sites during AF, but the documentation was limited. Therefore, only limited effects of rotational activation ablation at high-DF and/or continuous CFAE sites following PVI could be concluded.

Does Additional Electrogram-Guided Ablation After Linear Ablation Reduce Recurrence After Catheter Ablation for Longstanding Persistent Atrial Fibrillation? A Prospective Randomized Study.

BACKGROUND: Although circumferential pulmonary vein isolation (CPVI) catheter ablation may not be sufficient for long-standing persistent atrial fibrillation (L-PeAF), it is not clear which ablation strategy is beneficial in addition to CPVI. We sought to investigate whether additional complex fractionated atrial electrogram (CFAE)-guided ablation improves clinical outcomes in L-PeAF patients who exhibit continuous atrial fibrillation (AF) after CPVI and linear ablation (Line). METHODS AND RESULTS: This study enrolled 137 L-PeAF patients (71.4% male, 61.6±10.9 years old) who underwent radiofrequency catheter ablation. We conducted CPVI+Line based on the Dallas lesion set (posterior box+anterior line) after baseline CFAE mapping in all patients. If AF was defragmented (terminated or changed to atrial tachycardia), the procedure was stopped (AF-Defrag group, n=29). If AF was maintained after CPVI+Line, we mapped the CFAE again and randomly assigned the patient to the CPVI+Line group (n=54) or the additional CFAE ablation group (CPVI+Line+CFAE group, n=54). L-PeAF was defragmented during CPVI+Line in 21.2% of patients (29/137, AF-Defrag group). The mean CFAE cycle length was prolonged (P<0.001), and CFAE area (CFAE cycle length <120 milliseconds) was reduced (P<0.001) after CPVI+Line in the remaining patients. Procedure time was longer in the CPVI+Line+CFAE group than the CPVI+Line group (P=0.023), but procedure-related complication rates did not vary. During 22.3±13.2 months of follow-up, the clinical recurrence rates were 17.2% in the AF-Defrag group, 18.5% in the CPVI+Line group, and 32.1% in the CPVI+Line+CFAE group (log rank, P=0.166). CONCLUSIONS: Although CPVI+Line reduces and localizes CFAE area, additional CFAE ablation after CPVI+Line does not improve the clinical outcomes of catheter ablation in patients with L-PeAF.

Spatial reproducibility of complex fractionated atrial electrogram depending on the direction and configuration of bipolar electrodes: an in-silico modeling study.

Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in-silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: 11.5±0.7% variation, mini-cath: 7.1±1.2% variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: r=0.3055±0.2194 vs. mini-cath: 0.6074±0.0733, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one (38.3±4.6% vs. 22.3±1.4%, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters.

Recurrent atrial arrhythmias in the setting of chronic pulmonary vein isolation.

BACKGROUND: Atrial arrhythmias may still occur in patients after durable pulmonary vein isolation (PVI). OBJECTIVE: The purpose of this study was to examine the incidence of patients undergoing ablation for recurrent arrhythmia despite chronic PVI and their clinical outcomes. METHODS: Patients undergoing repeat left atrial ablation procedures were selected from a prospective registry. From this population, we identified patients with chronic PVI. Clinical characteristics, ablation strategies, and outcomes were analyzed. RESULTS: Between January 2003 and December 2013, 1045 patients underwent 1298 repeat left atrial procedures. Of these, 900 patients had atrial fibrillation (AF) and 145 had atrial flutter (AFL)/atrial tachycardia (AT). Fifty-two patients (5.0%; 27 with AF and 25 with AFL/AT) had chronic PVI and were included in the study. Patients were followed for 19.7 ± 5.6 months. In patients with AF, 11 (41%) had a non-PV trigger identified. Ablation strategies included non-PV trigger ablation (n = 11), empiric trigger-site ablation (n = 3), provoked arrhythmia ablation (n = 9), complex fractionated atrial electrogram ablation (n = 2), and linear ablation (n = 2). During follow-up, 9 (33%) had no recurrence, 7 (26%) had rare AF (≤2 episodes during follow-up ≥1 year), and 11 (41%) had AF recurrence. In patients with AFL/AT, 12 (48%) had no recurrence, 4 (16%) had rare recurrence (≤2 episodes during follow-up ≥1 year), and 9 (36%) had recurrence. CONCLUSION: In patients with PVI undergoing a repeat procedure during the time period studied, only a small portion had chronic PVI. A strategy of targeting non-PV triggers for AF and linear/focal ablation for AFL/AT may achieve long-term arrhythmia control in the majority of patients.

Left atrial electrophysiologic feature specific for the genesis of complex fractionated atrial electrogram during atrial fibrillation.

Complex fractionated atrial electrogram (CFAE) has been suggested to contribute to the maintenance of atrial fibrillation (AF). However, electrophysiologic characteristics of the left atrial myocardium responsible for genesis of CFAE have not been clarified. Non-contact mapping of the left atrium was performed at 37 AF onset episodes in 24 AF patients. Electrogram amplitude, width, and conduction velocity were measured during sinus rhythm, premature atrial contraction (PAC) with long- (L-PAC), short- (S-PAC) and very short-coupling intervals (VS-PAC). These parameters were compared between CFAE and non-CFAE regions. Unipolar electrogram amplitude was higher in CFAE than non-CFAE during sinus rhythm, L-, S- and VS-PAC (1.82 ± 0.73 vs. 1.13 ± 0.38, p < 0.001; 1.44 ± 0.54 vs. 0.92 ± 0.35, p < 0.001; 1.09 ± 0.40 vs. 0.70 ± 0.27, p < 0.001; 0.76 ± 0.30 vs. 0.53 ± 0.25 mV, p < 0.001). Laplacian bipolar electrogram amplitude was also higher in CFAE than non-CFAE during sinus rhythm, L-, S- and VS-PAC. Unipolar electrogram width was similar in CFAE and non-CFAE. Laplacian bipolar electrogram width was wider in CFAE than non-CFAE during L-, S- and VS-PAC (85.5 ± 6.8 vs. 79.6 ± 4.5, p < 0.001; 96.1 ± 9.7 vs. 84.5 ± 5.9, p < 0.001; 122.4 ± 16.0 vs. 99.6 ± 9.6 ms, p < 0.001), but not during sinus rhythm. The conduction velocity was slower in CFAE during sinus rhythm, L-, S- and VS-PAC than non-CFAE (1.7 ± 0.3 vs. 2.4 ± 0.4, p < 0.001; 1.4 ± 0.3 vs. 2.0 ± 0.5, p < 0.001; 1.2 ± 0.3 vs. 1.7 ± 0.5, p < 0.001; and 0.9 ± 0.3 vs. 1.4 ± 0.4 m/s, p < 0.001). CFAE was generated in the high amplitude atrial myocardium with slow and non-uniform conduction properties which were pronounced associated with premature activation, suggesting that heterogeneous conduction produced in high amplitude region contributes to the genesis of CFAE.