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Introduction: The effectiveness and safety of 50 W, high-power, short-duration (HPSD) ablation in superior vena cava isolation (SVCI) for patients with atrial fibrillation (AF) have been reported. However, the acute outcomes of SVCI combined with 90 W/4 s, very high-power, short-duration (vHPSD) ablation remain unknown. In this study, we aimed to investigate a novel approach that combines 50 W-HPSD and 90 W/4 s-vHPSD ablation in SVCI and to elucidate the characteristics, outcomes, and safety of this approach by comparing SVCI with conventional ablation index (AI)-guided middle-power, middle-duration (MPMD) ablation., Methods: Overall, 126 patients who underwent AF ablation with SVCI using the QDOT MICRO TM catheter were retrospectively reviewed; one group underwent SVCI with a combined approach of HPSD and vHPSD ablation (50 W/90 W group, n = 73) and another group underwent AI-guided MPMD ablation (30-40 W group, n = 53). This study compared the procedural details, radiofrequency (RF) ablation profiles, and complications. The RF settings used in the 50 W/90 W group were 50 W/7 s for the lateral segment close to the phrenic nerve and 90 W/4 s for the nonlateral segment., Results: The 50 W/90 W group required a significantly shorter procedural time (3.2 vs. 5.9 min, p < .001), shorter RF duration (42.0 vs. 162.0 s, p < .001), and lower RF energy (2834 vs. 5480 J, p < .001) than the 30-40 W group. Procedural success, first-pass SVCI, number of RF applications, and SVC reconnection after isoproterenol loading were comparable between the groups. The maximum tip-electrode temperature of the multi-thermocouple system was significantly higher in the 50 W/90 W group than in the 30-40 W group (50.0°C vs. 47.0°C, p < .001). No complications, such as phrenic nerve injury or bleeding requiring transfusion, were observed in either group., Conclusions: The combined approach of 50 W/7 s-HPSD and 90 W/4 s-vHPSD ablation resulted in successful and safe SVCI with shorter procedural time, shorter RF duration, and lower RF energy., (© 2024 Wiley Periodicals LLC.)

Background: We hypothesized that high-resolution activation mapping during sinus rhythm (SR) in Koch's triangle (KT) can be used to describe the most delayed atrial potential around the atrioventricular node and evaluated whether ablation targeting of this potential is safe and effective for the treatment of patients with typical atrioventricular nodal reentrant tachycardia (AVNRT)., Methods: We conducted a prospective, non-randomized, observational study using high-resolution activation mapping from the sinus node to KT with a PENTARAY or OCTARAY catheter using the CARTO 3 cardiac mapping system (Biosense Webster) during SR in 62 consecutive patients (22 men; age [mean ± standard deviation] = 55 ± 14 years) treated for typical AVNRT at our institution from August 2021 to March 2023., Results: In all cases, the most delayed atrial potential was observed near the His potential within KT. Ablation targeting of this potential helped successfully treat each case of AVNRT, with a junctional rhythm observed at the ablation site. Initial ablation was deemed successful in 55/62 patients (89%); in the remaining seven patients, lesion expansion resolved AVNRT. One procedural complication occurred, namely, a transient atrioventricular block lasting 45 s. One patient experienced a transient tachycardic episode by the 1-month follow-up, but no further episodes were noted up to the 1-year follow-up., Conclusion: Activation mapping at KT during SR with the high-resolution CARTO system clearly revealed the most delayed atrial potential near the His potential within KT. Targeting this potential was a safe and effective treatment method for patients with typical AVNRT in our study., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: The superior transseptal approach (STA) for mitral valve surgery is associated with a higher risk of developing macroreentrant incisional atrial flutter (AFL) than the left atrial approach. This study aimed to describe the linear lesions for the complex AFL circuit after the STA and to propose an option for the linear ablation target site., Methods: Of the 26 patients who underwent radiofrequency catheter ablation for AFL after mitral valve surgery, data from seven patients with STA incisions were retrospectively analyzed., Results: All patients who had undergone the STA had incisional AFL rotated in a long loop within the right atrium (RA) and cavo-tricuspid isthmus (CTI)-dependent AFL. The linear lesions were created in the CTI, the superior RA vestibule, and between the RA-free wall incision or the septal incision and the inferior vena cava. Procedural success was achieved with dual linear lesions in the CTI and superior RA vestibule. Two of seven patients had AFL recurrence during a mean observation period of 22.5 ± 16.7 months. The circuits of recurrent AFL were CTI-dependent AFL and perimitral AFL, respectively. No AFL recurrence was noted with reconduction of the superior RA vestibular lesion., Conclusion: Dual linear lesions in the CTI and superior RA vestibule are an effective treatment option for RA macroreentrant AFL after the STA., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Differential pacing technique to confirm mitral isthmus (MI) block is sometimes challenging due to destroyed tissues after extensive ablation. The purpose of this study is to set an endpoint of MI ablation using conduction time around the mitral annulus (MA)., Methods: Forty-five consecutive patients with persistent atrial fibrillation who received MI linear ablation were included. The geometry and activation times of the left atrium around the MA were collected using a multipolar catheter before ablation. During coronary sinus (CS) pacing, the time between the stimulus and the wave-front collision at the opposite side of the MA (defined as T/2) was calculated, and the doubled value was defined as the estimated perimitral conduction time (E-PMCT). The endpoint for complete MI block was when the stimulus (at distal CS) minus the maximal delayed potential (St-MDP) on the MI interval reached the E-PMCT., Results: St-MDP reached E-PMCT during MI ablation in 44/45 patients. Among these 44 patients, differential pacing revealed bidirectional block in 39/44 (88.6%), whereas in 5/44 (11.4%), the differential pacing was not possible because of the loss of capture of local potentials due to extensive applications around the linear line. In one patient, the St-MDP did not reach E-PMCT (E-PMCT: 148 ms, St-MDP :130 ms) and differential pacing revealed no MI block. E-PMCT values (median 176 ms) correlated strongly with St-MDP (median 185 ms, P < 0.0001, R = 0.98)., Conclusions: Although E-PMCT differs between individuals, the value is significantly correlated with the St-MDP. This technique may be useful in providing an individual endpoint of MI ablation as an alternative to differential pacing., (© 2018 Wiley Periodicals, Inc.)

Purpose: Achieving complete mitral isthmus (MI) conduction block for atrial fibrillation (AF) ablation remains challenging. We hypothesized that transseptal puncture (TSP) at the anteroinferior aspect of the atrial septum (anteroinferior TSP) could shorten the distance to the MI and improve catheter contact and stability, enabling complete MI block. This study investigated the efficacy of anteroinferior TSP for MI ablation in AF patients., Methods: Three hundred and twenty consecutive patients (mean age: 62 ± 9 years, 84 % male) with persistent AF undergoing AF ablation, including MI ablation, were enrolled. MI ablation was performed through the conventional (posterior) TSP site (group C, n = 170) or the anteroinferior TSP site (group A, n = 150)., Results: Left atrial diameter (LAD) enlargement was greater in group A than in group C (45.8 ± 5.3 mm vs. 44.1 ± 5.0 mm, p = 0.002). Complete MI block at the initial session was significantly higher in group A than in group C (141/150 [94 %] vs. 144/170 [85 %], p = 0.011). At the repeat session for AF recurrence, the rate of persistent complete MI block was significantly higher in group A than in group C (36/48 [75 %] vs. 28/67 [42 %], p < 0.001). LAD (p = 0.011) and left ventricular diastolic dimension (p = 0.037) were significant predictors of failed MI block, while anteroinferior TSP was significantly associated with successful MI block (p < 0.001)., Conclusion: Anteroinferior TSP could improve the initial success rate and long-term persistence of complete MI block for AF ablation.

Background: We aimed to determine whether differing foci in paroxysmal atrial fibrillation (PAF) affected the long-term outcome of catheter ablation (CA)., Methods: A total of 865 consecutive PAF patients (age, 61±10years; 670 male) undergoing initial AF ablation were included. After pulmonary vein (PV) isolation, superior vena cava (SVC) isolation was performed for SVC foci; other non-PV foci were focally ablated. Long-term outcomes were compared among patients with SVC foci (Group SVC), other non-PV foci (Group Non-PV), and those without these foci (Group PV)., Results: Groups PV, SVC, and Non-PV contained 740 (85.8%), 57 (6.6%), and 68 (7.6%) patients, respectively. Structural heart disease (P=0.01) and duration of AF history (P=0.04) were significantly associated with Group Non-PV, and female sex (P=0.0002) was significantly associated with Group SVC. AF recurrence-free rates at 5years in Group PV, SVC, and Non-PV were 62.0%, 66.3%, and 49.3%, respectively (P=0.03), after the initial CA, and 84.7%, 83.9%, and 77.0%, respectively (P=0.02), after the final CA. The duration of AF history (HR, 1.04, P<0.0001) and left atrial dimension (HR, 1.37 per 10mm increase, P=0.0003) were significant predictors of AF recurrence after the initial CA. Although Group Non-PV was weakly associated (HR 1.38, P=0.08) with AF recurrence, Group SVC was not associated with AF recurrence., Conclusions: Long-term outcome of CA of PAF was significantly worse in patients with non-PV foci other than SVC foci. These foci may affect the outcome not independently but as an aspect of atrial remodeling., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: Although several studies have reported an association between atrial fibrillation (AF) and alcohol, the impact of alcohol consumption on the outcome after catheter ablation (CA) for AF has not been discussed. We aimed to elucidate the effect of alcohol consumption on the outcome of CA for paroxysmal AF., Methods and Results: We examined 1361 consecutive patients with paroxysmal AF (mean age, 61±11 years, 334 women) who underwent CA, including 623 (45.8%) patients who consumed alcohol. The clinical characteristics and outcomes of CA were compared between patients who did and did not consume alcohol. No significant differences were seen in the left atrial size, duration of AF history, and incidence of nonpulmonary vein foci between 2 groups (P=NS). Although the AF recurrence-free rate after the initial CA was higher in patients who did not consume alcohol (261/623 [41.9%] versus 252/738 [34.1%]; mean follow-up, 44.4±30.7 months; P=0.003), the outcome after the final CA was similar between 2 groups (patients who consumed alcohol: 111/628 [17.7%] versus patients who did not consume alcohol: 138/738 [18.7%]; mean follow-up, 53.1±25.8 months; P=0.67). The frequency (hazard ratio 1.07 per 1 day/week increase, CI 1.00-1.15, P=0.04) of alcohol consumption was significantly associated with AF recurrence after CA., Conclusions: The frequency of alcohol consumption may be associated with AF recurrence after the initial CA for paroxysmal AF, but it may not affect the outcome after the final CA., (© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Background: Mitral regurgitation (MR) is generally classified as either primary (organic) or secondary (functional). Although patients with atrial fibrillation (AF) often exhibit MR, the relation between the etiology of MR and the outcome of catheter ablation (CA) remains unknown. We conducted this study in order to elucidate this association., Methods: Among 1330 consecutive paroxysmal AF patients who underwent initial catheter ablation in our institution, 92 patients (62 men, mean age 65 ± 7 years) who had moderate or severe MR were included in this study; 46 were classified to have primary and the remaining 46 to have secondary MR by preoperative echocardiography. These patients were prospectively monitored after the CA., Results: During a mean follow-up period of 27.9 ± 28.8 months, AF recurred in 26/46 (56.6 %) of primary MR patients and in 15/46 (32.6 %) of those with secondary MR (P < 0.02). Although univariate analysis found that diabetes, left atrial volume indexed by body surface area (LAVI), and primary MR were significantly associated with AF recurrence, primary MR (hazard ratio (HR), 2.47; 95 % confidence interval (CI), 1.30-4.88; P = 0.006) and LAVI (HR, 1.03/1 mL/m(2) increase; 95 % CI, 1.00-1.06; P = 0.03) remained significant predictors on multivariate analysis. The AF recurrence-free rate was lower in patients with primary MR after both the initial and final CA., Conclusion: In patients with paroxysmal AF and moderate or severe MR, primary MR may increase the risk of AF recurrence after the initial and final CA.

Introduction: Stroke can be a life-threatening complication of atrial fibrillation (AF) catheter ablation. Uninterrupted warfarin treatment contributes to minimizing the risk of stroke complications., Methods and Results: This was a prospective, open-label, randomized, multicenter study assessing the safety and efficacy of apixaban for the prevention of cerebral thromboembolism complicating AF catheter ablation. Two hundred patients with drug-resistant AF were equally assigned to take either apixaban (5 mg or 2.5 mg twice daily) or warfarin (target international normalized ratio, 2-3) for at least 1 month before AF ablation. Neither drug regimen was interrupted throughout the operative period. Diffusion-weighted magnetic resonance imaging was performed for all patients to detect silent cerebral infarction (SCI) after the ablation. Primary outcomes were defined as the occurrence of stroke, transient ischemic attack, SCI, or major bleeding that required intervention. The secondary outcome was minor bleeding. The groups did not statistically differ in patients' backgrounds or procedural parameters. During AF ablation, the apixaban group required administration of more heparin to maintain an activated clotting time > 300 seconds than the warfarin group (apixaban, 14,000 ± 4,000 units; warfarin, 9,000 ± 3,000 units). Three primary outcome events occurred in each group (apixaban, 2 SCI and 1 major bleed; warfarin, 3 SCI, P = 1.00), and 3 and 4 secondary outcome events occurred in the apixaban and warfarin groups (P = 0.70), respectively., Conclusion: Apixaban has similar safety and effectiveness to warfarin for the prevention of cerebral thromboembolism during the periprocedural period of AF ablation., (© 2016 Wiley Periodicals, Inc.)

Background: Paroxysmal atrial fibrillation (AF) is primarily triggered by pulmonary veins (PVs). However, non-PV AF foci may also trigger AF., Methods: We examined 207 patients (mean age, 62 ± 11 years; 166 men) who underwent a second catheter ablation (CA) and evaluated the clinical significance of non-PV AF foci on the outcomes., Results: Electrical reconnections between the PVs and left atrium (LA) were observed in 162 patients (78.3%). Non-PV AF foci were identified in 95 patients (45.9%, 60 patients with successfully ablated non-PV AF foci and 35 with unmappable non-PV AF foci). During a median follow-up period of 22.7 months, 61 patients (29.5%; 18/112 [16.1%] without non-PV AF foci vs. 20/60 [33.3%] with successfully ablated non-PV AF foci vs. 23/35 [65.7%] with unmappable non-PV AF foci, P < 0.0001) developed AF recurrence; 52 (85.2%) developed recurrence within 1 year. The presence of non-PV AF foci was a significant clinical predictor of AF recurrence after the second CA; successfully ablated non-PV AF foci increased the AF recurrence risk by 2.24 times (95% confidence interval [CI], 1.12-4.54; P = 0.02), and unmappable AF foci increased this risk by 5.58 times (95% CI, 2.73-11.63; P < 0.0001)., Conclusion: Nearly half of the patients had non-PV AF foci at the second CA session. AF recurred after the second CA session in approximately 30%, with most recurrences happening within 1 year. The presence of non-PV AF foci significantly increased the AF recurrence risk after a second CA. When non-PV AF foci were unmappable, the AF recurrence rate was extremely high., (© 2015 Wiley Periodicals, Inc.)

Aims: This study investigated whether disappearance patterns of pulmonary vein (PV) potentials (PVPs) during PV isolation (PVI) affect the outcome of catheter ablation (CA) in patients with paroxysmal atrial fibrillation (PAF)., Methods and Results: Extensive PVI was performed in 1149 PAF patients (age, 61 ± 10 years). Clinical and demographic characteristics, ablation data, and follow-up outcomes were prospectively collected. During an initial CA, simultaneous disappearance of superior and inferior PVPs in both right and left PVs was observed in 464 (40.4%) patients (Group S). Atrial fibrillation-recurrence free rates at 1, 3, and 5 years after the initial CA in Group S were 78.9, 71.9, and 68.1%, respectively, which were higher than those in Group Non-S (P = 0.004). However, those were similar after the final CA between both groups. The incidence of PV-left atrium (LA) electrical reconnection was significantly lower in Group S than in Group Non-S in the second (Group S, 65.6% vs. Group Non-S, 82.1%; P = 0.004) and third (Group S, 8.3% vs. Group Non-S, 47.6%; P = 0.03) CAs. Furthermore, the reconnections more frequently occurred on the side of PVs where simultaneous PVP elimination had not been achieved at the initial CA. Simultaneous disappearance of superior and inferior PVPs in both right and left PVs independently reduced the risk of AF recurrence after the initial CA by 26%., Conclusions: The simultaneous disappearance of superior and inferior PVPs in both right and left PVs is associated with less frequent PV-left atrium reconnection and may yield a better clinical outcome after the initial CA., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Aim: Atrial fibrillation (AF) ablation can result in oesophageal injuries that lead to atrio-oesophageal fistulae, a life-threatening complication. This study aimed to evaluate whether oesophageal cooling could prevent oesophageal lesions complicating AF ablation., Methods and Results: We randomly assigned 100 patients with drug-resistant AF to an oesophageal cooling group or a control group. In the oesophageal cooling group, we injected 5 mL of ice water into the oesophagus prior to radiofrequency (RF) energy delivery adjacent to the oesophagus. If the oesophageal temperature reached 42°C, the RF energy delivery was stopped, and the ice water injection was repeated. In the control group, oesophageal cooling was not applied. Oesophageal endoscopy was performed 1 day after the catheter ablation, and lesions were qualitatively assessed as mild, moderate, or severe. The numbers of ablation sites with an oesophageal temperature of >42°C were 1.7 ± 1.4 and 2.6 ± 1.7 in the oesophageal cooling group and the control group, respectively (P = 0.04), and the maximal oesophageal temperature at those sites was 43.0 ± 0.6 and 44.7 ± 0.9°C (P < 0.0001). Oesophageal lesions occurred almost equally between the oesophageal cooling group [10 of 50 patients (20%)] and the control group [11 of 50 patients (22%)]. However, the severity of the oesophageal lesions was slightly milder in the oesophageal cooling group (three moderate, seven mild) than in the control group (three severe, one moderate, seven mild)., Conclusion: Oesophageal cooling may alleviate the severity of oesophageal lesions but does not reduce the incidence of this complication under the specific protocol evaluated here., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)

Background: Catheter ablation is now an alternative approach to antiarrhythmic drug therapy for patients with symptomatic atrial fibrillation (AF). We focused on younger patients in whom the prevalence of AF is low, and we sought clinical factors associated with unsuccessful ablation outcomes., Methods and Results: Among 1983 consecutive symptomatic patients who underwent AF ablation procedures, 95 patients (4.8%), age ≤ 40 years, were prospectively included. Of them, 64 had paroxysmal AF, and the remaining 31 had persistent AF. All patients underwent pulmonary vein isolation and cavotricuspid isthmus ablation. When AF recurred, redo ablations were performed if the patients desired. The mean number of ablation procedures was 1.3 ± 0.6 times per patient. During the follow-up of 40 [27.8-49.6] months, sinus rhythm was maintained in 86 patients (90.5%) without any antiarrhythmic drugs, but not in the remaining 9 patients (9.5%). Low body mass index (BMI) and persistent AF were associated with unsuccessful ablation procedures. In multivariate logistic regression analysis, a low BMI had the most significant value, with an odds ratio of 7.33 (p=0.022). The receiver operating characteristic curve demonstrated a BMI cut point of 22.1 kg/m(2), with an area under the curve of 0.773., Conclusion: In symptomatic younger AF patients, a low BMI was an independent clinical factor for unsuccessful AF ablation outcomes., (Copyright © 2013 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Purpose: The study aim was to compare the incidence of esophageal injuries between different temperature probes in the monitoring of esophageal temperature during atrial fibrillation (AF) ablation., Methods: One hundred patients with drug-resistant AF were prospectively and randomly assigned into two groups according to the esophageal temperature probe used: the multi-thermocouple probe group (n = 50) and the deflectable temperature probe group (n = 50). Extensive pulmonary vein (PV) isolation was performed with a 3.5-mm open irrigated tip ablation catheter by using a radiofrequency (RF) power of 25-30 W. In both groups, the esophageal temperature thermocouple was placed on the area of the esophagus adjacent to the ablation site. When the esophageal temperature reached 42 °C, the RF energy delivery was stopped. Esophageal endoscopy was performed 1 day after the catheter ablation., Results: No differences existed between the two groups in terms of clinical background and various parameters related to the catheter ablation, including RF delivery time and number of RF deliveries at an esophageal temperature of >42 °C. Esophageal lesions, such as esophagitis and esophageal ulcers, occurred in 10/50 (20 %) and 15/50 (30 %) patients in the multi-thermocouple and deflectable temperature probe groups, respectively (P = 0.25). Most lesions were mild to moderate injuries, and all were cured using conservative treatment., Conclusion: The incidence of esophageal injury was almost equal between the multi-thermocouple temperature probe and the deflectable temperature probe during esophageal temperature monitoring. Most of the esophageal lesions that developed during esophageal temperature monitoring were mild to moderate and reversible.

Background: Although catheter ablation (CA) is a standard treatment for atrial fibrillation (AF), its long-term efficacy remains unclear. This study aimed to elucidate the incidences of AF recurrence and of progression from paroxysmal to persistent AF, after CA, in patients with paroxysmal AF., Methods and Results: We examined the incidence of AF recurrence and AF progression in 1220 consecutive patients (mean age, 61 years), with symptomatic paroxysmal AF, undergoing CA, based on extensive pulmonary vein isolation and focal ablation for nonpulmonary vein foci. AF recurrence-free survival probabilities at 5 years were 59.4% after the initial CA and 81.1% after the final CA (average, 1.3 procedures). During a median follow-up period of 47.9 (range, 5.3-123.3) months after the initial CA, AF progressed from paroxysmal to persistent in 15 (1.2%) patients (0.3%/y). The duration of AF history (hazard ratio [HR], 1.03; P<0.0001), number of ineffective antiarrhythmics (HR, 1.09; P=0.005), and left atrial diameter indexed by the body surface area (HR, 1.05; P=0.001) were significant predictors of AF recurrence. Patient age (HR, 1.12; P=0.0001) and left atrial diameter indexed by the body surface area (HR, 1.26; P=0.0006) were significantly associated with AF progression. Patients aged≤65 years and with a left atrial diameter indexed by the body surface area of ≤24.0 mm/m2 did not develop AF progression for ≤10 years after the initial CA., Conclusions: Although the long-term follow-up revealed the effect of CA on preventing AF recurrence, repeated CA sessions might be required. The rate of progression from paroxysmal to persistent AF was 0.3%/y.

Aims: The outcomes of catheter ablation (CA) in patients with paroxysmal atrial fibrillation (PAF) who are undergoing haemodialysis (HD) have not been fully elucidated. This study aimed to determine the impact of HD on CA outcome in these patients., Methods and Results: We examined 1364 consecutive PAF patients (mean age, 61 ± 10 years) who underwent CA, including 32 (2.3%) patients undergoing HD. The patients undergoing HD had a significantly lower body mass index (P < 0.0001), higher CHADS2 score (P = 0.006), and higher prevalence of structural heart disease (P < 0.0001), hypertension (P = 0.002), and congestive heart failure (P = 0.02). Echocardiography indicated a larger left atrial diameter (P < 0.0001) and left ventricular diameter (P = 0.0002) in the HD patients. Haemodialysis was a significant predictor of AF recurrence (hazard ratio 2.56; 95% confidence interval 1.56-4.03; P = 0.0004) in the overall population. Sinus rhythm maintenance rates in the HD patients at 1, 3, and 5 years were 42.3, 37.6, and 19.7%, respectively, after the first procedure, and 64.7, 54.9, and 47.1%, respectively, after the final procedure (median, 2; range, 1-2 procedures); these rates were significantly lower than those in the non-HD patients (P < 0.0001). The 5-year survival rate was 78.1% in the HD patients., Conclusion: Haemodialysis was significantly associated with AF recurrence after CA for PAF. However, an ∼50% success rate for sinus rhythm maintenance without antiarrhythmic drug therapy in HD patients suggested that CA could be an option for the treatment of AF.

Background: The aim of this study was to investigate the incidence and predictors (which have not previously been fully elucidated) of late-phase thromboembolism (TE) after catheter ablation (CA) for paroxysmal atrial fibrillation (AF)., Methods and Results: We studied 1,156 consecutive patients (61±10 years; 891 men; CHADS2score, 0.8±1.0) after CA for symptomatic paroxysmal AF and examined the details of late-phase TE. During a follow-up of 49.5±21.9 months (median, 47 months; range, 6-113 months) after CA, 9 patients (0.78%) developed late-phase TE, all of which were ischemic stroke. Of these, 5 patients with AF recurrence experienced cardioembolism; the AF was asymptomatic at recurrence. The remaining 4 without AF recurrence experienced cardioembolism (n=1), small-vessel occlusion (n=1), large-artery atherosclerosis (n=1), and stroke of other determined etiology (n=1). On Kaplan-Meier analysis patients with structural heart disease (P=0.003), AF recurrence after the final CA (P=0.01), prior stroke (P=0.002), CHADS2score ≥2 (P=0.0002), left ventricular ejection fraction <50% (P<0.0001), and spontaneous echo contrast on transesophageal echocardiogram (P=0.0004) had a significantly higher risk of late-phase TE. Multivariate analysis indicated that CHADS2score ≥2 (HR, 4.49; 95% CI: 1.08-22.56; P=0.04) independently predicted late-phase TE., Conclusions: The incidence of TE was low after CA for paroxysmal AF, but CHADS2score ≥2 independently increased the risk of late-phase TE.

Background: Catheter ablation (CA) has become a standard treatment for patients with atrial fibrillation (AF). However, gender-related differences associated with CA of paroxysmal AF (PAF) remain unclear., Methods: We compared 1124 consecutive patients (mean age, 61 ± 10 years; male, n=864) with PAF scheduled for CA between the genders., Results: Females were significantly older (p<0.0001), and had a lower body-mass-index (p=0.02), smaller left atrial dimension (LAD; p=0.04), larger LAD indexed by the body-surface-area (LADI; p<0.0001) and better left ventricular ejection fraction (p<0.0001) at baseline. Ischemic heart disease (p=0.007) was more frequent in males, whereas hypertrophic cardiomyopathy (p=0.007) and mitral stenosis (p=0.001) were more frequent in females. More additional procedures were performed to eliminate non-pulmonary vein foci in females than males (p<0.05), but those locations were similar between the genders. The incidence of procedure-related complications was similar between genders (p=0.73). Sinus rhythm was similarly maintained between females and males after the first CA (56.4% vs. 59.3% at 5 years, p=0.24), but was significantly lower in females after the last CA (76.5% vs. 81.3% at 5 years, p=0.007). More females did refuse multiple CA procedures (especially a second one) than males (37.8% in females vs. 27.4% in males, p=0.02). The age (HR, 0.98/y, p=0.01), duration of AF (HR, 1.04/y, p=0.0001), number of failed anti-arrhythmic-drugs (HR, 1.10, p=0.03) and LADI (HR, 1.89 per 10mm/m(2), p=0.001) were significantly associated with AF-recurrence in males, but not in females., Conclusions: Specific differences and similarities between the genders were observed in PAF patients undergoing CA., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Introduction: This study aimed to elucidate the clinical characteristics and management of periesophageal vagal nerve injury complicating the ablation of atrial fibrillation (AF)., Methods and Results: A total of 3,695 patients with drug-resistant AF underwent extensive pulmonary vein isolation at our institution. Either a nonirrigated or an irrigated ablation catheter was employed, with radiofrequency power of 25-40 W. Esophageal temperature was monitored in 3,538 patients: when the esophageal temperature reached 42°C radiofrequency delivery was stopped. A total of 11 patients (60 ± 11 years, 10 males) were diagnosed as having a periesophageal vagal nerve injury after the AF ablation. Symptoms included nausea, vomiting, bloating, constipation, and gastric pain, which occurred within 72 hours after the procedure. Gastrointestinal fluoroscopy and/or endoscopy revealed gastric hypomotility (10 patients) and pyloric spasm (1 patient). Intravenous erythromycin (3 mg/kg every 8 hours) was effective in relieving symptoms in 5 patients, and the patient with pyloric spasm underwent esophagojejunal anstomosis. Eight patients almost fully recovered within 40 days; however, 3 patients suffered from severe symptoms for 3-12 months. This complication occurred in 4 of the 157 patients (2.5%) who did not have esophageal temperature monitoring, and 7 of the 3,538 (0.2%) who did (P = 0.0007). The 3 patients with persistent severe symptoms received no esophageal temperature monitoring., Conclusion: The clinical course and severity of the periesophageal vagal nerve injury varied, but most patients finally recovered with conservative treatment. Radiofrequency delivery under esophageal temperature monitoring might reduce both the incidence and the severity of this complication., (© 2013 Wiley Periodicals, Inc.)

Introduction: This study aimed to determine the effects of continuing warfarin administration during the periprocedural period of catheter ablation for atrial fibrillation (AF) on the prevention of stroke complications and to evaluate the management of hemorrhagic complications occurring with this approach., Methods and Results: A total of 3,280 patients undergoing AF catheter ablation at our institution were divided into 2 groups: the first 1,953 patients who discontinued warfarin 3-4 days before AF ablation and were bridged with heparin (warfarin-discontinued group), and the last 1,327 patients who continued warfarin throughout the periprocedural period (warfarin-continued group). Symptomatic stroke or transient ischemic attack occurred in 13/1,953 patients (0.67%) in the warfarin-discontinued group and in 2/1,327 patients (0.15%) in the warfarin-continued group (P = 0.021). None of the patients with therapeutic international normalized ratio at the time of the procedure had periprocedural thromboembolism in the warfarin-continued group. Major hemorrhagic complications occurred in 26/1,953 patients in the warfarin-discontinued group (1.3%; 25 with cardiac tamponade and 1 with retroperitoneal bleeding), and in 15/1,327 patients in the warfarin-continued group (1.1%; 14 with cardiac tamponade and 1 with abdominal wall bleeding) (P = 0.80). Of the 14 warfarin-continued patients with cardiac tamponade, 13 were administered prothrombin complex concentrate (PCC) and vitamin K; the bleeding was stopped safely without surgical repair., Conclusion: The continuation of warfarin during the periprocedural period of AF ablation could reduce the incidence of stroke without increasing hemorrhagic complications. When cardiac tamponade occurred with this approach, it was safely treated with PCC and vitamin K., (© 2012 Wiley Periodicals, Inc.)

Background: Pulmonary vein reconnection after electrical isolation is commonly observed in the context of atrial fibrillation ablation and is associated with recurrent atrial tachyarrhythmias. Adenosine test was been performed to identify acute dormant conduction immediately after pulmonary vein isolation at index procedure. However, the utility of adenosine test at repeat procedure has not been reported., Methods and Results: We report 5 paroxysmal atrial fibrillation cases without any structural heart disease in which dormant thoracic vein conduction was associated with recurrent atrial tachyarrhythmias. All patients had undergone circumferential ipsilateral pulmonary vein isolation at the index procedure. Superior vena cava isolation was performed if superior vena cava-triggered atrial fibrillation was identified. At the index procedure, adenosine test did not provoke venous reconduction. At the repeat procedure, adenosine provoked clinical arrhythmia in 4 out of 5 cases after transient reconnection between culprit thoracic vein and atrium despite absence of reconnection at the start of the procedure. After the elimination of the dormant conduction gaps, all patients were free from recurrent arrhythmia., Conclusions: Adenosine provokes dormant thoracic vein conduction associated with the late recurrence of atrial tachyarrhythmias after previous thoracic vein isolation. Thus, adenosine provocation test can specifically help identify and target the cause of recurrent atrial arrhythmia.

Background: Pulmonary vein antral isolation (PVAI) is a recommended treatment for symptomatic drug-refractory paroxysmal atrial fibrillation (PAF). PAF naturally progresses toward persistent AF with an increase in the frequency and duration of AF. The objective of this study was to evaluate whether the preprocedural AF frequency had an impact on the AF recurrence after PVAI in patients with symptomatic PAF., Methods and Results: A total of 362 consecutive patients (61.0 ± 9.8 years; 274 males) with drug-refractory PAF who underwent PVAI were included. The preprocedural frequency of PAF was daily, weekly, monthly, and yearly in 145 (40.1%), 112 (30.9%), 90 (24.9%), and 15 (4.1%) patients, respectively. There were no significant differences in any of the preprocedural variables between the four groups, except for the number of ineffective antiarrhythmic drugs (AADs). PVAI was successfully performed in all patients. At 12 months after the initial procedure, 63.5% of the entire group of patients were free of AF recurrences without any AADs, respectively. A Cox regression multivariate analysis of the variables including the AF frequency, age, gender, duration of AF, presence of hypertension or structural heart disease, left atrial size, left ventricular ejection fraction, and body mass index demonstrated that the AF frequency was not an independent predictor of AF recurrence after a single ablation procedure (P = 0.194)., Conclusions: This study demonstrated that the preprocedural AF frequency did not predict AF recurrence after PVAI in patients with PAF. From the clinical point of view, an additional AF classification based on the preprocedural AF frequency might not be valuable in patients undergoing PVAI., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)

Aims: This study aimed to elucidate the clinical characteristics of massive air embolism occurring during atrial fibrillation (AF) ablation., Methods and Results: Of 2976 patients undergoing AF ablation, 5 patients complicated by serious air embolism were examined. Atrial fibrillation ablation was performed with the use of three long sheaths for circular mapping and ablation catheters under conscious sedation. Two patients had air spontaneously introduced through a haemostasis valve of the long sheaths, at the end of long apnoea caused by the sedation, even though the catheters were placed within the long sheaths. The remaining three patients, all of whom also exhibited long apnoea, had air entry at the circular mapping catheter exchanges. Air accumulated in the right and left ventricles, left atrial appendage, right coronary artery, and ascending aorta. Haemodynamic collapse and hypoxaemia occurred in all and two patients, respectively, and supportive treatment and the accumulated air were aspirated. ST elevation, haemodynamic collapse, and hypoxaemia persisted for 10-35 min; however, all patients recovered completely. After we changed the sedative to one with less respiratory depressive effects and the timing of the saline flush at the circular mapping catheter exchanges, we never experienced such serious complications any further., Conclusion: Serious air embolism can occur in patients with long apnoea under sedation during AF ablation with the use of long sheaths. Supportive therapy and air aspiration were effective in resolving the complication. A sedative that causes less respiratory depression and the timing of the saline flush were important for preventing air embolism.

Background: Kidney function is a known predictor of cardiovascular morbidity and mortality. Although patients with atrial fibrillation (AF) often have kidney dysfunction, less is known about the association between AF and kidney function. We sought to assess changes in kidney function after catheter ablation of AF., Methods and Results: Patients who underwent catheter ablation of AF were recruited for the present prospective study. Estimated glomerular filtration rate (eGFR) was evaluated before and 1 year after the ablation. Three hundred eighty-six patients (paroxysmal AF, 135; persistent AF, 106; longstanding persistent AF, 145) were studied. Their baseline eGFR was 68 ± 14 mL · min(-1) · 1.73 m(-2). Sixty-six percent and 26% of patients had eGFR of 60 to 89 and 30 to 59 mL · min(-1) · 1.73 m(-2), respectively. Overall, 278 patients (72%) were arrhythmia free over a 1-year follow-up. In patients free from arrhythmia, eGFR increased 3 months later and was maintained until 1 year, whereas in patients with recurrences, eGFR had decreased over 1 year. Changes in eGFR over 1 year in patients free from arrhythmia differed significantly compared with those with recurrences (3 ± 8 versus -2 ± 8 mL · min(-1) · 1.73 m(-2); P<0.0001). In all quartiles of baseline eGFR, changes in eGFR over 1 year after the ablation were greater in patients free from arrhythmia compared with those with recurrences., Conclusion: Elimination of AF by catheter ablation was associated with improvement of kidney function over a 1-year follow-up in patients with mild to moderate kidney dysfunction.

The objective of this study was to investigate the prevalence, electrophysiologic properties, and clinical implications of dissociated pulmonary vein (PV) activity after PV antrum isolation (PVAI) in patients with paroxysmal atrial fibrillation (AF). One hundred seventy-three consecutive patients (61 ±10 years old, 141 men) with drug-refractory paroxysmal AF who underwent AF ablation were analyzed. After identification of arrhythmogenic foci, PVAI was performed in all patients. Of the total 346 isolated ipsilateral PVs, 97 (28.0%) were silent, 35 (10.1%) demonstrated isolated ectopic beats, 209 (60.4%) demonstrated a regular ectopic rhythm, and 5 (1.4%) demonstrated fibrillatory activity. The culprit thoracic vein was identified in 77 patients (44.5%). After isolation of ipsilateral PVs, venous activity was observed in 68 (79.1%) and 178 (68.5%) PVs among the 86 PVs with AF triggers and 260 PVs without AF triggers, respectively (p = 0.06). There was no significant difference in the incidence of acute PV reconnections exposed by adenosine triphosphate between the 97 silent ipsilateral PVs and 209 ipsilateral PVs with dissociated PV activity after the PVAI (20.6% vs 19.1%, p = 0.78). After a mean follow-up of 48.7 ± 7.9 months there was no significant difference in rates of freedom from atrial tachyarrhythmias after a single procedure between patients with and those without dissociated activity (62.1% vs 63.3%, p = 0.74, log-rank test). In conclusion, although dissociated PV activity appearing after PV isolation is an important electrophysiologic finding to prove bidirectional conduction block between the left atrium and the PV during the procedure, the clinical implications might be limited., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: To examine the long-term clinical outcomes of patients undergoing catheter ablation (CA) for either paroxysmal (PAF) or persistent atrial fibrillation (PsAF) using an extensive pulmonary vein isolation (EPVI)-based strategy., Methods and Results: 574 patients (61 ± 9 years; 449 men) with drug-refractory PAF or PsAF underwent CA. Ipsilateral pulmonary veins (PVs) were isolated with extensive antral ablation. A cavotricuspid isthmus line with bidirectional conduction block was created and all non-PV triggers of AF ablated at the index procedure. Left atrial linear ablation was performed in patients with PsAF if AF remained inducible. Patients with recurrent atrial arrhythmias had previous lesions assessed and consolidated. With mean follow up of 27 ± 14 months after the final procedure, 480 patients (83.6%) were in sinus rhythm without antiarrhythmic drugs (1.4 ± 0.6 procedures). The single procedure success rate without antiarrhythmic drugs was 65.5%. A late recurrence (>6 months after the initial procedure) and very late recurrence (>12 months) were seen in 1.6% and 1.7% of patients, respectively. All patients with a late recurrence had PV reconnection, with one patient also demonstrating a non-PV trigger. In comparison, non-PV triggers of AF accounted for 85.7% of very late recurrences with no evidence of PV reconduction., Conclusions: EPVI-based CA is effective in maintaining sinus rhythm in patients with PAF and PsAF over the long term. Recurrent AF after 1 year is mainly due to non-PV triggers, suggestive of an ongoing pathological process.

Background: A low incidence of thromboembolic events after successful catheter ablation of atrial fibrillation (AF) during a mid-term follow-up period was recently reported. However, because the incidence of such events over the long term is unknown, we investigated the late incidence of thromboembolic events after catheter ablation., Methods and Results: Patients with paroxysmal and persistent AF undergoing catheter ablation and being followed up for at least 24 months formed the study group (n = 524); 82 patients (16%) had CHADS₂ scores of at least 2. Mean follow-up was 44 ± 13 months. Warfarin was discontinued in 400 (93%) of 429 patients (82% of 524 patients) without AF recurrence. None of the patients without AF recurrence suffered thromboembolic events, whereas 3 of 95 patients (3%) with AF recurrence did (P < 0.001). One of the 3 was a late AF recurrence occurring > 12 months after catheter ablation. There were 2 nonfatal major hemorrhagic events in patients with AF recurrence who continued on warfarin, but no hemorrhagic events were observed in patients free from AF (P = 0.002)., Conclusions: Maintenance of sinus rhythm after catheter ablation of AF was associated with a lower incidence of thromboembolic events during long-term follow-up >3 years. This result suggests that catheter ablation reduces thromboembolic events if patients continue anticoagulation regardless of the ablation outcome.

Unlabelled: AF Ablation in Patients With Valvular Heart Disease., Background: The purpose of this study is to evaluate the efficacy of atrial fibrillation (AF) ablation in patients with moderate valvular heart disease (VHD)., Methods: In total, 534 consecutive patients who underwent AF ablation were enrolled. Patients with a history of valve surgery or other structural heart disease were excluded. Patients with clinically moderate VHD (group-1, n = 45) were compared with those without VHD (control group-2, n = 436). Ipsilateral pulmonary vein antrum isolation (PVAI) was performed with a double Lasso technique in all the patients. Left atrial (LA) linear ablation was undertaken in persistent AF patients, if AF was inducible after PVAI., Results: Patients in group-1 were significantly older and had a larger LA. PVAI was successfully achieved in all the patients. Patients in group-1 received LA linear ablation more frequently during the index procedure. After a median of 26 months from the index procedure, the freedom from AF was significantly lower in group-1 than group-2 off antiarrhythmic drugs (AADs) (47% vs 69%, P = 0.002). Although there were more number of total procedures in group-1 than group-2, the freedom from AF was lower at median 24 months after the last procedure (78% vs 87%, P = 0.038). There was no significant difference in the freedom from AF on AADs (91% vs 95%, P = 0.356) or complication rate between the 2 groups. Atrial tachycardia following the index procedure was observed more frequently in group-1 (P = 0.001)., Conclusion: The patients with VHD undergoing AF ablation are less likely to remain in sinus rhythm at long term without AADs than those without VHD., (© 2010 Wiley Periodicals, Inc.)

Background: We sought to characterize patients with persistent atrial fibrillation (AF) who were successfully treated by ablation targeting the left atrium (LA)., Methods and Results: Ninety-three patients (58±10 years, 79 male) undergoing ablation of persistent AF were studied. During the first procedure, ablation was performed in the LA and coronary sinus, consisting of pulmonary vein isolation, linear ablation, and electrogram-based ablation. During follow-up after the first procedure, 35 patients (38%) remained free from tachyarrhythmias, 27 patients (29%) had atrial tachycardia, and 31 patients (33%) had AF. Duration of persistent AF according to medical history and whether AF was terminated by ablation were associated with the outcome (P=0.005, P=0.004, respectively). In multivariate analysis, the duration of persistent AF was the only predictor of freedom from AF (sinus rhythm or atrial tachycardia) (odds ratio, 0.80 for a 1-year increase; 95% confidence interval, 0.67 to 0.95; P=0.01). Of 31 patients in whom AF recurred during follow-up, electrogram-based ablation was performed in the right atrium in 26 patients. Sixteen of those patients (62%) remained free from AF during follow-up. Overall, 82% of patients were free from any tachyarrhythmias at 2-year follow-up after a median of 2 procedures., Conclusions: Patients with shorter duration of persistent AF were more likely to be free from AF by LA ablation. Right atrial ablation may provide incremental efficacy in patients who are refractory to LA ablation.

Aims: Bepridil is highly effective in terminating persistent atrial fibrillation (AF). Despite continued treatment, a high rate of AF recurrence after pharmacological cardioversion (PC) with bepridil has been reported. Bepridil therapy is also associated with significant adverse effects., Methods and Results: This retrospective case-control study included 82 patients with persistent AF (PEF). Group 1 (22 patients) comprised cases undergoing AF ablation following attempted PC with bepridil. Group 2 (60 patients) comprised control that underwent AF ablation without bepridil pre-treatment. In Group 1, 15 patients (68%) restored sinus rhythm (SR) with bepridil (SR group) and 7 continued to have AF (AF group). SR group underwent extensive pulmonary vein isolation (EPVI) alone. AF group and Group 2 underwent linear ablation after EPVI, if AF was inducible. At the end of 18 +/- 5 months off antiarrhythmic drugs, the AF-free rate was 87% in SR group, 29% in AF group, and 72% in Group 2 (72 vs. 29%, P = 0.02)., Conclusion: Following AF ablation in patients who successfully restored SR with bepridil pre-treatment, AF-free rate was significantly higher than in those who failed to do so. Conversion to SR with bepridil might help select the optimal patients with PEF for catheter ablation.

Background: Mapping of recurrent atrial tachycardia (AT) after extensive ablation for long-lasting persistent atrial fibrillation (AF) is complex. We sought to describe the electrophysiological characteristics of localized reentry occurring after ablation of long-lasting persistent AF., Methods: Out of 70 patients undergoing catheter ablation of long-lasting persistent AF, 9 patients (13%, 55 +/- 8 years, 8 males) in whom localized reentry was demonstrated in a repeat ablation were studied. Localized reentry was defined as reentry in which the circuit was localized to a small area and did not have a central obstacle. The mechanism of AT was determined by electroanatomical and entrainment mapping., Results: Nine localized reentries with cycle length of 243 +/- 41 ms were mapped in 9 patients. The location of AT was the left atrial appendage in 4 patients, anterior left atrium in 2, left septum in 2, and mitral isthmus in 1. In all ATs, a critical isthmus of <10 mm in width was identified in the vicinity of the prior linear lesions or ostia of isolated pulmonary veins. Ablation of the critical isthmus, which was characterized by continuous low-voltage activity (median voltage: 0.15 mV, mean duration: 117 +/- 31 ms), terminated AT and rendered it noninducible. Additionally, ablation was performed for all of inducible ATs. At 11 +/- 7 months after the procedure, 8 of 9 patients (89%) were free from any arrhythmias., Conclusions: After ablation of long-lasting persistent AF, localized reentry may arise from a site in the vicinity of the prior ablation lesions. Ablation of the critical isthmus eliminates the arrhythmia.

Radiofrequency catheter ablation is widely performed as an effective treatment for recurrent, drug-resistant atrial fibrillation (AF). Recently, various types of ablation strategies, such as extensive encircling pulmonary vein (PV) isolation, linear ablation and complex fractionated electrogram-guided ablation, have been used to achieve a high efficacy for all types of AF. However, several complications (thromboembolic events, PV stenosis and atrio-esophageal fistula etc) with an incidence of 3.9-6%, have been reported. It is important to understand the incidence, prevention and management of complications in order to develop safe ablation strategies.

Introduction: Catheter ablation on the left atrial posterior wall has been reported to potentially damage the esophagus or periesophageal vagal nerve. The aim of this study was to evaluate the efficacy of esophageal temperature monitoring (ETM) in preventing esophageal or periesophageal vagal nerve injury in patients with atrial fibrillation (AF) undergoing pulmonary vein (PV) isolation., Methods: This study included 359 patients with drug-refractory AF who underwent extensive PV isolation. The first 152 patients were treated without ETM (non-ETM) and the last 207 with ETM. In the ETM group, the esophageal temperature (ET) was measured with a deflectable temperature probe that was placed close to the ablation electrode, and the radiofrequency energy applications were stopped when the ET reached 42 degrees C., Results: In all patients in the ETM group, the ET increased to 42 degrees C in at least one site by 28 +/- 14 seconds, mostly along the right side of the left PVs, especially near the left inferior PV. Less energy (6.3 +/- 1.9 x 10(4) J) was required for PV isolation in the ETM group than that in the non-ETM (6.8 +/- 1.9 x10(4) J, P = 0.03). Gastric hypomotility owing to periesophageal nerve damage was observed in three patients in the non-ETM group, but in none in the ETM (P = 0.02). The recurrence rates of AF did not differ between the two groups (non-ETM, 29%; ETM, 27%)., Conclusion: Titration of the duration of the ablation energy delivery while monitoring the ET could prevent periesophageal nerve injury due to the AF ablation, without decreasing the success rate of maintaining sinus rhythm.

Background: The current study aimed to investigate the effect of ablation therapy on the quality of life (QOL) in patients with atrial fibrillation (AF) by using a questionnaire specific for AF., Methods and Results: A total of 86 patients (paroxysmal/chronic, 61/25) with drug-resistant AF undergoing extensive pulmonary vein isolation were recruited for the study. The QOL was quantitatively assessed by the Atrial Fibrillation Quality of Life Questionnaire at baseline, and 1, 3 and 6 months after the ablation. Sinus rhythm was maintained in 48/61 (79%) of the paroxysmal AF group, and 15/25 (60%) of those in the chronic AF group during 6 months after the initial ablation procedure. Among the patients without any AF recurrences, patients with chronic AF exhibited a substantial improvement in the QOL at 1 month after the procedure, and it remained unchanged until the end of the follow-up period. However, in the patients with paroxysmal AF, the QOL level gradually increased over a 6-month period. The patients with recurrent AF exhibited no improvement in the QOL., Conclusion: Although the clinical course of the QOL improvement was different, both paroxysmal and chronic AF patients gained better QOL to maintain sinus rhythm by means of catheter ablation.

Background: Achievement of complete conduction block in the cavotricuspid isthmus (CTI) is a curative ablation technique in patients with common atrial flutter (AFL). The present study was a prospective comparison of the efficacy of 2 ablation strategies in patients with common AFL: the continuous and point-by-point radiofrequency (RF) delivery techniques., Methods and Results: Forty patients with common AFL were randomly assigned to either a group treated with a continuous RF delivery or to a group undergoing point-by-point RF ablation. In the first group, the RF energy was continuously delivered during a slow drag of the catheter tip from the tricuspid annulus to the inferior vena cava without stopping the application. In the second group, the RF ablation was performed using a point-by-point approach for 60 s at each point. All patients underwent ablation with an 8-mm-tip ablation catheter with a power limit of 50 W and a target temperature of 55 degrees C. Complete CTI conduction block was achieved in all patients. The patient characteristics, including the anatomy of the CTI estimated by 3-dimensional computed tomography, were no different between the 2 groups. The procedure time (time from the start of RF delivery to the completion of CTI block), fluoroscopic time and total RF energy required to create the CTI block between the continuous and point-by-point groups were 7.3+/-5.6 vs 21.2+/-22.2 min (p<0.01), 7.2+/-4.4 vs 16.2+/-14.1 min (p<0.05), and 15,631+/-6,001 vs 24,072+/-16,140 joules (p<0.05), respectively. There were no complications or recurrences of AFL during the follow-up period in any of the patients., Conclusion: In the curative treatment of common AFL, the continuous RF delivery approach could shorten the procedure and fluoroscopic time and reduce the total RF energy compared with the point-by-point RF ablation approach.