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Background: Durable pulmonary vein isolation (PVI) is critical in reducing recurrence after radiofrequency catheter ablation for atrial fibrillation (AF). The VISITAG Module, an automatic annotation system that takes account of catheter stability and contact force (CF), might be useful in accomplishing this., Methods and results: In 49 patients undergoing VISITAG-guided AF ablation (group A), we set the following automatic annotation criteria: catheter stability range of motion ≤1.5 mm, duration ≥5 s, CF ≥5 g, time ≥25% and tag diameter at 6 mm. We used ablation >20 s and force-time integral >150 gs at each site, then moved to the next site where a new tag appeared that overlapped with the former tag. Results and outcome were retrospectively compared for 42 consecutive patients undergoing CF-guided AF ablation without this algorithm (group B). Successful PVI at completion of the initial anatomical line was more frequent in group A than B (66.3% vs. 36.9%, P=0.0006) while spontaneous PV reconnection was less frequent (14.2% vs. 30.9%, P=0.0014) and procedure time was shorter (138±35 min vs. 180±44 min, P<0.001). One-year success rate off anti-arrhythmic drugs was higher in group A (91.8% vs. 69.1%, log rank P=0.0058)., Conclusions: An automated annotation algorithm with an optimal setting reduced acute resumption of left atrium-PV conduction, shortened procedure time, and improved AF ablation outcome.

Background: The purpose of this study is to analyze the impact of average contact force (CF) and its regional variability during pulmonary vein isolation (PVI) for atrial fibrillation (AF) on periprocedural parameters and midterm outcome., Methods: This retrospective cohort study enrolled 57 drug-refractory AF patients who underwent initial PVI for AF using an open-irrigated CF catheter (SmartTouch Thermocool, Biosense Webster, Diamond Bar, CA, USA). Thirty patients were assigned to a lower CF (LCF) group (average CF≤10g) and 27 patients to a higher CF (HCF) group (average CF>10g). The relationship between CF and clinical outcome was analyzed., Results: Patients were followed-up for 317±57 days after PVI. The CF was 8.1±1.3g in the LCF group and 12.4±1.5g in the HCF group. Higher average CF was associated with shorter ablation time (28±6min vs. 36±9min, p=0.0002) and lower radiofrequency energy delivery (79±18 vs. 99±26, p=0.0016) for PVI. The rate of acute PV reconnection (APVR) was similar in both groups (LCF group 60% vs. HCF group 44%, p=0.36). Four patients (13%) in the LCF group and nine patients (33%) in the HCF group experienced AF-recurrence. Average CF did not impact on AF-recurrence during midterm clinical outcome (p=0.09 by log-rank test). In the non-recurrence group (n=44), average CF was higher at left posterosuperior PV and right anteroinferior PV than that in the recurrence group (n=13) (p=0.012 and p=0.004, respectively)., Conclusions: Higher average CF decreased ablation time and radiofrequency energy delivery for PVI, but did not decrease APVR rate or improve midterm clinical outcome., (Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: This study aimed to evaluate the association between left atrial (LA) structural remodeling and very late recurrence [VLR; initial recurrence >12 months after catheter ablation (CA)] after successful CA for non-paroxysmal atrial fibrillation (AF)., Methods: We retrospectively evaluated 63 patients who underwent initial, single ablation for drug-refractory persistent or long-standing persistent AF and those who had no recurrence in the first year after CA. We followed patients for a mean of 3.2±1.5 years and divided them into VLR and no-recurrence (NR) groups. Before and 3 months after ablation, all patients were subjected to 64-slice multidetector computed tomography scanning to estimate LA volume, including maximum and minimum volume during the cardiac cycle (LAMaxV and LAMinV, respectively), and the LA emptying fraction., Results: VLR occurred in 21 patients. The reduction rate of LAMaxV after CA was significantly larger in the NR group than in the VLR group (25±19% vs. 5±18%, p=0.0002). Receiver operating characteristic analysis was performed to determine the best cut-off values in the prediction of VLR. The highest area-under curve was obtained with post-CA LAMinV [0.828 (95% confidence interval, 0.712-0.912), p<0.0001], with a best cut-off value of 44mL (sensitivity 81.0%, specificity 81.0%)., Conclusions: Persistent LA structural remodeling after initially successful CA for non-paroxysmal AF may be an important risk factor for VLR., (Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: Regional differences in optimal contact force (CF) to prevent acute pulmonary vein reconnection (APVR) during catheter ablation for atrial fibrillation (AF) remain unclear., Objective: The purpose of this study was to evaluate regional difference in optimal CF during AF ablation., Methods: This single-center observational study evaluated data from 57 consecutive drug-refractory AF patients (mean age, 62 ± 11 years; 43 males) who underwent initial pulmonary vein isolation (PVI) using the THERMOCOOL® SMARTTOUCH™ (Biosense Webster, Diamond Bar, CA, USA) catheter from June to August 2013. APVR was defined as the time-dependent reconnection >20 minutes after initial PVI and/or reconnection evoked by intravenous adenosine administration (20 mg). Point-by-point relationships between the reconnected points and their CF values were evaluated., Results: Total 72 gaps causing APVR were observed. Of a total of 4,421 ablation points, 285 (6.4%) were associated with APVR. The average CF value of the points with APVR was significantly lower than that of those without (APVR vs. no APVR; 7.5 ± 6.7 g vs. 9.9 ± 8.4 g; P < 0.0001). The areas under the curve and optimal CF values differed between segments (range 0.593-0.761 and 10-22 g, respectively). The optimal CF value was highest in bottom of the right PV and posterosuperior right PV segments (22 g) and lowest in posteroinferior right PV segment (10 g)., Conclusions: There was a regional difference in optimal CF values to prevent APVR, and the optimal CF value to prevent APVR with >95% probability was 10-22 g, depending on the individual peri-PV segments., (© 2014 Wiley Periodicals, Inc.)

Aims: Although several prognostic factors for atrial fibrillation (AF) recurrence after catheter ablation (CA) have been reported, predictors of very late recurrence (VLR; initial recurrence >12 months after ablation) remain unidentified. This study investigated clinical variables predictive of VLR after CA for AF., Methods and Results: This retrospective single-centre cohort study evaluated data from 1016 consecutive drug-refractory AF patients who underwent single CA for AF from July 2004 to May 2010. After excluding 324 patients with a short follow-up period (<1 year) and 300 patients with recurrence within a year of CA, 392 patients were included. Study subjects were divided into two groups on the basis of VLR presence. Preoperative clinical variables were evaluated as predictors of VLR using the Cox proportional hazards model. The annual rate of VLR was 7.6% after single CA. Univariate analysis revealed that hypertension [hazard ratio (HR) 1.77, 95% confidence interval (CI) 0.93-3.37, P = 0.08], obesity (HR 1.84, 95% CI 0.98-3.45, P = 0.06), long-standing persistent AF (HR 2.35, 95% CI 1.08-5.11, P = 0.03), and abnormally high preoperative C-reactive protein (CRP) levels >0.5 mg/dL (HR 4.28, 95% CI 2.03-9.03, P < 0.0001) were associated with VLR. In the multivariate model, only abnormally high preoperative CRP level was an independent predictor of VLR (HR 4.9, 95% CI 2.3-10.7, P < 0.0001)., Conclusion: Even after a year without AF, VLR occurred annually in 7.6% cases. Continued vigilance for VLR after CA is clinically desirable, especially for patients with abnormally high preoperative CRP levels.

Aims: Diastolic late mitral annular velocity (a') measured by transthoracic echocardiography (TTE) is reported to represent left atrial (LA) pump function and the severity of LA remodelling. The purpose of this study is to investigate the association between a' and LA blood stasis in patients with non-valvular paroxysmal atrial fibrillation., Methods and Results: We enrolled 138 consecutive patients with non-valvular paroxysmal atrial fibrillation who had spontaneous sinus rhythm at the time of echocardiography. Using TTE, a' was determined as an average of tissue Doppler velocities measured at septal and lateral mitral annuli. Transoesophageal echocardiography was also performed on the same day as TTE, and spontaneous echo contrast (SEC) and LA appendage flow velocity were examined. Spontaneous echo contrast was observed in 21 (15%) patients. Patients in the lowest quartile of a' (≤6.4 cm/s) demonstrated SEC more frequently (44 vs. 6%, P < 0.0001) and had lower LA appendage flow velocity (39 ± 13 vs. 53 ± 16 cm/s, P < 0.0001) than those in the other quartiles. Receiver-operating characteristic curve analysis showed that the best cut-off value of a' was 7.0 cm/s for the prediction of SEC with a sensitivity of 80%, specificity of 81%, and predictive accuracy of 80%. Multivariate analysis revealed that decreased a' (OR = 0.61, P = 0.0026) was independently associated with SEC., Conclusion: Decreased a' may be a useful parameter for the estimation of LA blood stasis in patients with paroxysmal atrial fibrillation.

Aims: In patients with paroxysmal atrial fibrillation (AF), the P-wave signal-averaged electrocardiogram often demonstrates a low-amplitude potential at the terminal part of filtered P-wave (atrial late potential: ALP), which would originate from delayed pulmonary vein (PV) potentials. The aim of this study was to investigate the impact of PV isolation on P-wave morphology, and explore the association between ALP and AF recurrence after ablation., Methods and Results: We enrolled 88 consecutive paroxysmal AF patients scheduled for ablation. The signal-averaged electrocardiogram was obtained at baseline and 1 day after ablation. An ALP was defined as a P-wave duration of ≥ 130 ms and a root-mean-squared voltage of the terminal 20 ms of ≤ 2.0 μV. A pre-procedural ALP was found in 37 (42%) patients and a post-procedural ALP was found in 26 (30%) patients. We completed PV isolation in all patients and followed them for 16 ± 4 months. The AF recurrence rate was 30% (26 patients) and was similar between patients with and without pre-procedural ALP (27 vs. 31%, respectively, P = 0.66); however, AF recurrence was significantly higher in patients with than without post-procedural ALP (54 vs. 19%, respectively, P = 0.001). In multivariate logistic regression analysis, post-procedural ALP was independently associated with AF recurrence (odds ratio = 4.22, 95% confidence interval = 1.52-11.7)., Conclusion: Pulmonary vein isolation can modify ALP in a substantial number of patients with paroxysmal AF. Post-procedural ALP is associated with increased risk of future AF recurrence.

The major mechanism underlying the early recurrence of atrial fibrillation (AF) after ablation is mainly reconnection of the isolated pulmonary vein (PV); however, the mechanism responsible for very late recurrence (VLR) has not been fully elucidated. The purpose of the present study was to investigate the mechanism underlying VLR. The study population included 150 consecutive patients with AF who underwent a second session of catheter ablation because of recurrence. We divided them into 2 groups according to the point of initial AF recurrence: the late recurrence group (LR group, initial recurrence 3 to 12 months after ablation, n = 124) and the VLR group (initial recurrence >12 months after ablation, n = 26). We identified PVs with ectopic foci (trigger PVs) in the first procedure and checked their electrical reconnection in the second procedure. The prevalence of PV reconnection and trigger PV reconnection were significantly lower in the VLR group than in LR group (LR vs VLR, 90% vs 69% and 48% vs 27%, p = 0.007 and p = 0.045, respectively). In the VLR group, left ventricular systolic and diastolic function were significantly worse than in the LR group, and more patients in the VLR group required non-PV trigger ablation in the second session than did those in the LR group (30% vs 54%, p = 0.034). In conclusion, electrical PV reconnection contributed less to VLR than to LR. Progression of the AF substrate might be an important mechanism responsible for VLR., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Concealed sick sinus syndrome may become manifest after restoration of sinus rhythm by ablation in patients with long-standing persistent atrial fibrillation (AF). The purpose of this study was to investigate the association between the preprocedural ventricular rate during AF and sinus node function in patients with long-standing persistent AF., Methods: Consecutive patients (n = 102) who underwent ablation for long-standing persistent AF were enrolled. We measured the ventricular rate during AF before ablation in the absence of antiarrhythmic drugs. Sinus node function was assessed by electrophysiological study and serial Holter recordings after ablation., Results: Patients in the lowest quartile of ventricular rate during AF had longer corrected sinus node recovery time (1.06 ± 1.39 seconds) than those in the other quartiles (0.54 ± 0.31 seconds; P = 0.006) and lower mean heart rate on 24-hour Holter recording 3 months after ablation (68 ± 9 beats/min vs 75 ± 10 beats/min, P = 0.01). During a mean follow-up of 23 ± 10 months, sick sinus syndrome necessitating permanent pacemaker implantation developed in five (5%) patients, and multivariate analysis revealed that a low ventricular rate during AF rate was an independent risk factor for sick sinus syndrome (odds ratio = 0.90 for a 1 beat/min increase in AF rate, P = 0.04)., Conclusions: A low preprocedural ventricular rate during AF indicates the existence of sinus node dysfunction after restoration of sinus rhythm by ablation in patients with long-standing persistent AF., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)

Background: We investigated the possibility that a frequent trigger action might play a role in the development of persistent atrial fibrillation (PeAF) and the presence of a substrate., Methods and Results: In 263 consecutive patients who underwent catheter ablation (CA) for PeAF, electric cardioversion was performed at the beginning of the procedure to determine the presence or absence of an immediate recurrence of AF (IRAF). We defined an IRAF as a reproducible AF recurrence within 90 s after restoration of sinus rhythm by electric cardioversion. We performed a mean±SD of 1.3±0.5 sessions of CA, including pulmonary vein isolation and ablation of the premature atrial contractions that triggered the IRAF (IRAF triggers), and observed the patients for 17 (10-27) months. An IRAF was observed in 70 patients (27%), but we could not ablate the IRAF triggers in 16 (23%) of these IRAF patients. The recurrence rate of PeAF was higher in patients with an unsuccessful IRAF trigger ablation than in those with successful IRAF trigger ablation (63% versus 11%; P<0.001). A multivariable analysis also revealed that an unsuccessful IRAF trigger ablation was 1 of the independent predictors of recurrent PeAF (odds ratio, 10.9; 95% CI, 3.4-36.7)., Conclusions: In the PeAF patients with an IRAF, successful elimination of the IRAF triggers, in addition to pulmonary vein isolation, resulted in a successful CA. These results imply that such triggers play a major role in the AF persistence in these PeAF patients.

Background: The effect of atrial fibrillation (AF) ablation on left atrial (LA) function has not been sufficiently determined., Methods: We enrolled 115 consecutive patients with paroxysmal or persistent AF that underwent AF ablation. Multidetector computed tomography was performed in sinus rhythm before and 3 months after ablation to evaluate LA volume (LAV) and function. Estimates of maximum and minimum LAV were used to calculate LA emptying fraction (LAEF) ([maximum-minimum LAV]/maximum LAV × 100)., Results: AF ablation significantly decreased maximum LAV (59.0 ± 20.4 to 53.3 ± 16.7 cm(3) , P = 0.001), and maintained LAEF (44.5 ± 13.1% to 43.7 ± 10.9%, P = 0.49). The larger the baseline maximum LAV, the greater the decrease in LAV after ablation, and a smaller baseline LAEF was associated with a larger recovery of LAEF after ablation (regression coefficient =-0.45 and -0.56, respectively, P < 0.0001). Multivariable analyses revealed that an impaired baseline LAEF was an independent predictor of an improvement in LA function (an increase in LAEF of >10%; odds ratio [OR] = 0.88, P < 0.0001), while an older age and preserved baseline LAEF were independently associated with a deterioration of LA function (a decrease in LAEF of >10%; OR = 1.06, P = 0.03; and OR = 1.10, P = 0.0001)., Conclusions: AF ablation appears to have a beneficial effect on LA function in patients with impaired LA function at baseline. However, it may reduce LA function in patients with an older age and preserved baseline LAEF., (©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.)

Background: Estimation of left atrial (LA) pump function is important for the management of cardiac patients. The purpose of this study is to elucidate the role of mitral annular late diastolic velocity (A') determined by transthoracic echocardiography as a parameter to predict LA pump function., Methods and Results: One hundred and four consecutive patients that were scheduled for paroxysmal atrial fibrillation (AF) ablation, in whom both multi-detector computed tomography (MDCT) and echocardiography during sinus rhythm prior to ablation were performed, were enrolled in this study. To determine the echocardiographic parameters that most accurately represent LA pump function, the relationship between LA emptying fraction (LAEF) obtained by MDCT and echocardiographic parameters including A' were examined. A' was the only echocardiographic parameter that was significantly correlated with LAEF (r=0.59, P<0.0001). Receiver-operating characteristic curve analysis showed that when impaired LA booster pump performance was defined as an LAEF <30%, an A' cutoff value of 7.4 cm/s had a sensitivity of 93%, specificity of 81%, predictive accuracy of 83%, positive predictive value of 43% and a negative predictive value of 99%., Conclusions: A' is a simple, non-invasive and reliable method to estimate LA pump function in patients with paroxysmal AF.

Aim: The silhouette of the left atrial (LA) roof is characterized by the pulmonary veins (PVs) and left atrium, and may include the characteristics of the PV/left atrium arrhythmogenicity in patients with atrial fibrillation (AF). In this study, we examined the hypothesis that the characteristics of the LA roof could help us understand the electrophysiological information of the PVs/left atrium., Methods and Results: The study population consisted of 153 consecutive patients with AF. The shape of the LA roof was determined by simultaneous right- and left-pulmonary angiography and 64-slice multi-detector-row computed tomography. The silhouette was classified into a deep-V shape (A; n= 35), shallow-V (B; n= 76) shape, and flat or coved shape (C; n= 42) according to the PV/left atrium dominancy. The AF triggers from the PVs (A: 70% vs. B: 57% vs. C: 40%; P= 0.003) became significantly less and those from non-PV sites (A: 6% vs. B: 13% vs. C: 22%; P= 0.043) significantly greater, as the LA shape became flat. Burst-inducible atrial tachyarrhythmias after PV isolation (A: 51% vs. B: 65% vs. C: 79%; P= 0.001) and at the end of the catheter ablation (A: 12% vs. B: 24% vs. C: 36%, P= 0.016) significantly increased, as the LA roof shape became flat. Although the PV diameters did not differ among the three groups, the LA volume (A: 69.5 ± 24.1 vs. B: 85.2 ± 34.9 vs. C: 105.7 ± 45.4 mL; P< 0.001) significantly increased as the LA shape became flat., Conclusions: The shape of the LA roof allowed us to understand the structural and the electrophysiological information of the PVs/left atrium.

We investigated the relation between left ventricular diastolic dysfunction and left atrial appendage (LAA) thrombus in patients with atrial fibrillation (AF). We performed transesophageal echocardiography to examine LAA thrombus or spontaneous echo contrast (SEC) and to measure LAA emptying flow velocity in consecutive 376 patients with AF. We estimated diastolic filling pressure as the ratio of early transmitral flow velocity (E) to mitral annular velocity (e') on transthoracic echocardiogram. E/e' ratio in 28 patients (7.4%) with LAA thrombi was higher than that in patients without thrombus (18.3 ± 9.3 vs 11.4 ± 5.9, p <0.0001). The fourth quartile of E/e' (>13.6) consisted of 19 patients with thrombi and had a higher prevalence of thrombi than the others (p <0.0001). Multivariate regression analysis selected E/e' ≥13 as an independent predictor of LAA thrombus with an odds ratio of 3.50 (1.22 to 10.61) in addition to LA dimension and ejection fraction. Increased quartile of E/e' was negatively associated with LAA flow velocity and positively with rate of SEC. In conclusion, increased diastolic filling pressure is associated with a higher rate of LAA thrombus in AF, partly through blood stasis or impaired LAA function., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Aims: It has been reported that an inflammatory process is involved in the development of atrial fibrillation (AF). In this study, we examined the hypothesis that a pre-existent inflammatory response may enhance the recurrence of AF after catheter ablation (CA)., Methods and Results: A total of 257 consecutive AF patients undergoing CA were enrolled in this study. The C-reactive protein was assessed by a high-sensitive radio-immunoassay 1 day before the procedure. Of the clinical characteristics, an advanced age, structural heart disease, and the left atrial (LA) diameter were significantly increased when the C-reactive protein level was elevated. Atrial fibrillation occurrences were significantly increased when the C-reactive protein level was elevated. A multivariate analysis demonstrated that an elevated C-reactive protein level [hazard ratio (95% CI); 2.23 (1.04-4.35)], the LA diameter [1.26 (1.10-1.66)], and persistent AF duration [2.13 (1.13-3.79)] were independent factors related to the recurrence of AF after CA. In the procedural findings, burst-inducible AF after pulmonary vein (PV) isolation was significantly increased, and the incidence of AF from the PVs was significantly lower when the C-reactive protein level was elevated., Conclusion: An elevated C-reactive protein level was associated with atrial structural and electrical remodelling maintaining AF, and the increased re-entrant atrial substrate might increase the recurrence of AF after the CA procedure.