Randomized Comparison of Multipolar,Duty‐Cycled,Bipolar‐Unipolar Radiofrequency Versus Conventional Catheter Ablation for Treatment of Common Atrial Flutter

Comparison of Radiofrequency Versus Conventional Catheter Ablation. Introduction: Radiofrequency (RF) catheter ablation has been established as an effective and curative treatment for atrial flutter (AFL). Approved methods include a drag‐and‐drop method, as well as a point‐by‐point ablation technique. The aim of this study was to compare the acute efficacy and procedural efficiency of a multipolar linear ablation catheter with simultaneous energy delivery to multiple catheter electrodes against conventional RF for treatment of AFL. Methods: Patients presenting to our department with symptomatic, typical AFL were enrolled consecutively and randomized to conventional RF ablation with an 8‐mm tip catheter (ConvRF) or a duty‐cycled, bipolar‐unipolar RF generator delivering power to a hexapolar tip‐versatile ablation catheter (T‐VAC) group. For both groups, the procedural endpoint was bidirectional cavotricuspid isthmus block. Results: Sixty patients were enrolled, 30 patients each assigned to ConvRF and T‐VAC groups. Total procedure time (40.2 ± 15.8 min vs 60.5 ± 12.7 min), energy delivery time (8.5 ± 3.7 min vs 14.7 ± 5.2 min), radiation dose (14.5 ± 3.5 cGy/cm² vs 31.7 ± 12.1 cGy/cm²), and the minimum number of RF applications needed to achieve block (4.2 ± 2.4 vs 8.9 ± 7.2) were significantly lower in the T‐VAC group. In 7 patients treated with the T‐VAC catheter, bidirectional block was achieved with less than 3 RF applications, versus no patients with conventional RF energy delivery. Conclusion: The treatment of typical AFL using a hexapolar catheter with a multipolar, duty‐cycled, bipolar‐unipolar RF generator offers comparable effectiveness relative to conventional RF while providing improved procedural efficiency. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1109‐1113)     

Impact of patent foramen ovale on left atrial linear lesions in the context of atrial fibrillation ablation

Impact of PFO on LA Linear Ablation. Introduction: We investigated the impact of the mode of left atrial (LA) access via patent foramen ovale (PFO) versus transseptal (TS) puncture on LA linear lesions during atrial fibrillation (AF) ablation. Methods and Results: We investigated 139 (PFO: 25) consecutive patients who underwent mitral isthmus (MI) and/or LA roof linear ablation. Technical endpoint was completeness of linear lesions and duration of radiofrequency (RF) application. During the initial procedure, complete MI and LA roof blocks were created in 13 of 19 (68%) and 14 of 17 (82%) patients in the PFO group, and in 57 of 94 (61%) and 54 of 70 (74%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (11.1 ± 8.9 and 15.1 ± 7.6 minutes, P = 0.11), and LA roof (10.1 ± 3.5 and 8.3 ± 5.0 minutes, P = 0.21) between the 2 groups. Among 28 patients who underwent repeat linear ablation, complete MI and LA roof blocks were created in 3 of 4 (75%) and 0 of 1 (0%) patients in the PFO group, and in 16 of 21 (76%) and 7 of 10 (70%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (15.3 ± 8.3 and 19.5 ± 18.3 minutes, P = 0.71), and LA roof (19.0 and 10.3 ± 5.4 minutes, P = 0.19) between the 2 groups. Clinical outcomes at 12 months were also similar. Conclusion: There were no significant differences in the procedural success rates, durations of RF application, 12‐month clinical outcomes, and complication rates of LA linear ablation between the PFO and TS groups. Accessing the LA via a PFO is not an unfavorable approach toward LA linear ablation . (J Cardiovasc Electrophysiol, Vol. 22, pp. 846‐850, August 2011)     

Characteristics and significance of very early recurrence of atrial fibrillation after catheter ablation

Very Early Recurrence of AF. Introduction: Early restoration of sinus rhythm following ablation of atrial fibrillation (AF) facilitates reverse atrial remodeling and improves the long‐term outcome. The purpose of this study was to determine the predictors and outcome in patients with very early AF recurrences (< 2 days). Methods and Results: Ablation was performed in 339 consecutive AF patients (paroxysmal AF = 262). Biatrial voltage was mapped during sinus rhythm. If recurrent AF occurred within 2 days following the ablation, electrical cardioversion was performed to restore sinus rhythm. Very early recurrences of AF occurred in 39 (15%) patients with paroxysmal AF and 26 (34%) with nonparoxysmal AF. Patients with very early recurrence had a higher incidence of nonparoxysmal AF (40% vs 18.6%, P< 0.001), requirement of electrical cardioversion during procedure, larger left atrial (LA) diameter (43 ± 7 vs 39 ± 6 mm, P< 0.001), lower left ventricular ejection fraction (54 ± 10% vs 59 ± 7, P< 0.001), longer procedural time, and lower LA voltage (1.5 ± 0.7 vs 1.9 ± 0.8 mV, P< 0.001). A multivariate analysis revealed that the independent predictors of a very early recurrence were a longer procedural time and lower LA voltage. During a follow‐up of 13 ± 5 months, a very early recurrence did not predict the long‐term outcome of a single procedure recurrence in the patients with paroxysmal AF, but was associated with a late recurrence in the nonparoxysmal AF patients. Conclusion: Very early recurrence occurred in patients with paroxysmal AF is not associated with long‐term recurrence. Nonparoxysmal AF is an independent predictor of late recurrence of AF in patients with very early recurrence. (J Cardiovasc Electrophysiol, Vol. pp. 1‐6)     

Mitral isthmus ablation with and without temporary spot occlusion of the coronary sinus: a randomized clinical comparison of acute outcomes

Role of CS Occlusion for Mitral Isthmus Ablation . Objective: To evaluate the safety and outcomes of mitral isthmus (MI) linear ablation with temporary spot occlusion of the coronary sinus (CS). Background: CS blood flow cools local tissue precluding transmurality and bidirectional block across MI lesion. Methods: In a randomized, controlled trial (CS‐occlusion = 20, Control = 22), MI ablation was performed during continuous CS pacing to monitor the moment of block. CS was occluded at the ablation site using 1 cm spherical balloon, Swan–Ganz catheter with angiographic confirmation. Ablation was started at posterior mitral annulus and continued up to left inferior pulmonary vein (LIPV) ostium using an irrigated‐tip catheter. If block was achieved, balloon was deflated and linear block confirmed. If not, additional ablation was performed epicardially (power ≤25 W). Ablation was abandoned after ～30 minutes, if block was not achieved. Results: CS occlusion (mean duration ?27 ± 9 minutes) was achieved in all cases. Complete MI block was achieved in 13/20 (65%) and 15/22 (68%) patients in the CS‐occlusion and control arms, respectively, P = 0.76. Block was achieved with significantly small number (0.5 ± 0.8 vs 1.9 ± 1.1, P = 0.0008) and duration (1.2 ± 1.7 vs 4.2 ± 3.5 minutes, P = 0.009) of epicardial radiofrequency (RF) applications and significantly lower amount of epicardial energy (1.3 ± 2.4 vs 6.3 ± 5.7 kJ, P = 0.006) in the CS‐occlusion versus control arm, respectively. There was no difference in total RF (22 ± 9 vs 23 ± 11 minutes, P = 0.76), procedural (36 ± 16 vs 39 ± 20 minutes, P = 0.57), and fluoroscopic (13 ± 7 vs 15 ± 10 minutes, P = 0.46) durations for MI ablation between the 2 arms. Clinically uneventful CS dissection occurred in 1 patient Conclusions: Temporary spot occlusion of CS is safe and significantly reduces the requirement of epicardial ablation to achieve MI block. It does not improve overall procedural success rate and procedural duration. Tissue cooling by CS blood flow is just one of the several challenges in MI ablation. (J Cardiovasc Electrophysiol, Vol. 23, pp. 489‐496, May 2012)     

Results of Short‐Term and Long‐Term Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation Using Duty‐Cycled Bipolar and Unipolar Radiofrequency Energy

PV Isolation Using Bipolar/Unipolar RF Energy . Background: Electrical disconnection of the pulmonary veins (PV) plays an important role in the ablation of paroxysmal atrial fibrillation (AF). Antral ablation using a conventional steerable ablation catheter often is technically challenging and time consuming. Methods: Eighty‐eight patients (mean age 58 ± 11 years) with symptomatic paroxysmal AF underwent ablation with a circular mapping/ablation decapolar catheter (PVAC). Ablation was performed in the antral region of the PVs with a power‐modulated bipolar/unipolar radiofrequency (RF) generator using 8–10 W delivered simultaneously through 2–10 electrodes, as selected by the operator. Seven‐day Holter monitor recordings were performed off antiarrhythmic drugs at 3‐, 6‐, and 12‐month follow‐up, and patients were requested to visit the hospital in the event of ongoing palpitations. All follow‐up patients were divided into 2 groups: Group 1 with a follow‐up of less than 1 year and group 2 patients completing a 1‐year follow‐up. Results: Overall, 338 of 339 targeted PVs (99%) were isolated with the PVAC with a mean of 24 ± 9 RF applications per patient, a mean total procedure time of 125 ± 28 minutes, and a mean fluoroscopy time of 21 ± 13 minutes. Freedom from AF off antiarrhythmic drugs was found in 82 and 79% of group 1 and group 2 patients, respectively. No procedure‐related complications were observed. Conclusion: PV isolation by duty‐cycled unipolar/bipolar RF ablation can be effectively and safely performed with a circular, decapolar catheter. Twelve‐month follow‐up data compare favorably with early postablation results, indicating stable effects over time. (J Cardiovasc Electrophysiol, Vol. 21, pp. 399–405, April 2010)     

Completion of mitral isthmus ablation using a steerable sheath: prospective randomized comparison with a nonsteerable sheath

Completion of Mitral Isthmus Ablation. Background: Although mitral isthmus (MI) ablation in atrial fibrillation (AF) patients has been shown to be an effective ablative strategy, the establishment of the bidirectional conduction block of the MI is technically challenging. We investigated the usefulness of a steerable sheath for MI ablation in patients with persistent AF and its impact on the clinical outcome of persistent AF ablation. Methods: A total of 80 consecutive patients undergoing MI ablation were randomized to 1 of the following 2 groups: group S (using a steerable long sheath) or group NS (using a nonsteerable long sheath). MI ablation was performed by using an open‐irrigated ablation catheter with the guidance of a 3‐dimensional mapping system. The endpoint of the MI ablation was the achievement of a bidirectional block. Results: Bidirectional block through the MI was achieved in 87.5% (70/80) of patients with 14.0 ± 6.7 minutes of radiofrequency application. The bidirectional block was more frequently achieved in patients in group S compared to group NS (97.5% (39/40) vs 77.5% (31/40), P = 0.02). Additionally, epicardial ablation within the coronary sinus was less frequently required in group S compared to group NS (12.5% (5/40) vs 72.5% (29/40), P < 0.0001). Atrial tachycardia after the procedure more frequently occurred in the patients in whom MI block had not been achieved during the initial procedure (40.0% (4/10) vs 10.0% (7/70), P = 0.04). Conclusions: The MI block could be achieved in the majority of patients by using a steerable sheath. An incomplete MI block increased the risk of AT following persistent AF ablation. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1331‐1338, December 2011)     

Robotic navigation in catheter ablation for paroxysmal atrial fibrillation: midterm efficacy and predictors of postablation arrhythmia recurrences

Robotic Navigation in Ablation of Paroxysmal AF . Introduction: Remote navigation systems represent a novel strategy for catheter ablation of atrial fibrillation (AF). The goal of this study is to describe a single‐center experience with the electromechanical robotic system (Sensei, Hansen Medical) in treatment of patients with paroxysmal AF. Methods: Out of 200 patients who underwent robotically guided ablation for AF between 2007 and 2009 at our institute, 100 patients (29 women, age 56.5 ± 10 years) had paroxysmal AF refractory to antiarrhythmic drugs. Electroanatomic mapping using NavX system (St. Jude Medical) provided anatomical shell for subsequent circumferential ablation with robotic catheter (Artisan) loaded with a 3.5‐mm, open‐irrigation, cooled‐tip ablation catheter. Results: A mean of 69 radiofrequency current applications (duration 2082 ± 812 seconds) were delivered to achieve circumferential electrical isolation of pulmonary venous antra. Total procedural time reached 222 ± 54 minutes. The mean fluoroscopic time was 11.9 ± 7.8 minutes. There were no major procedure‐related complications. After a median follow‐up of 15 months (range 3‐28 months), 63% of the patients were free from any atrial arrhythmias ≥ 30 seconds after the single procedure. Success rate increased to 86% after 1.2 procedures. Multivariate analysis revealed that only predictor of recurrent AF/AT was shorter overall procedural time (207 ± 36 vs 236 ± 64 minutes in patients with and without recurrences, respectively, P = 0.0068). Conclusions: This study demonstrates feasibility and safety of robotic navigation in catheter ablation for paroxysmal AF. Midterm follow‐up documents success rate comparable to other technologies and potential for improvement in more extensive ablation along the ridges with thicker myocardium. (J Cardiovasc Electrophysiol, Vol. 22, pp. 534‐540 May 2011)     

Incidence of silent cerebral thromboembolic lesions after atrial fibrillation ablation may change according to technology used: comparison of irrigated radiofrequency, multipolar nonirrigated catheter and cryoballoon

AF Ablation Technologies and Silent Cerebral Ischemic Lesions. Introduction: Silent cerebral ischemic lesions have recently emerged as the most frequent complications after pulmonary vein isolation (PVI). To reduce thromboembolic complications, new types of catheters and energy source have been introduced in clinical practice. The study purpose is to compare the incidence of new silent cerebral ischemic events in patients with paroxysmal atrial fibrillation (PAF) undergoing PVI with different ablation technologies. Methods and Results: One hundred and eight patients (67% men; age 56 ± 9 years) with PAF were enrolled in a consecutive manner to undergo PVI performed with irrigated radiofrequency (RF) catheter (Group 1, 36 patients), multielectrode catheter (PVAC) associated with duty‐cycled RF generator (Group 2, 36 patients) and cryoballoon (Group 3, 36 patients). The protocol included a cerebral magnetic resonance imaging before and after the procedure. After PVI, the following patients showed new silent cerebral ischemic lesions at postprocedural cerebral MRI: 3 patients in Group 1 (8.3%), 14 patients in Group 2 (38.9%), 2 patients in Group 3 (5.6%). PVAC related to higher incidence of silent cerebral ischemic events compared to irrigated RF (P = 0.002) and cryoballoon (P = 0.001), whereas no statistical differences were found between irrigated RF catheter and cryoballoon groups (8.3% vs 5.6%, P = 0.5). At the multivariate analysis, the only independent predictor of new ischemic asymptomatic cerebral lesions after PVI was ablation performed with PVAC (OR 1.48 95% CI 1.19–1.62, P < 0.001). Conclusion: The incidence of silent cerebral lesions after PVI is different depending on technologies used: PVAC increases the risk of 1.48 times compared to irrigated RF and cryoballoon ablation. (J Cardiovasc Electrophysiol, Vol. 22, pp. 961‐968, September 2011)     

Substrate modification by pulmonary vein isolation and left atrial linear ablation in patients with persistent atrial fibrillation: its impact on complex-fractionated atrial electrograms

PV and Linear Ablation for CFAEs . Introduction: Linear ablations in the left atrium (LA), in addition to pulmonary vein (PV) isolation, have been demonstrated to be an effective ablation strategy in patients with persistent atrial fibrillation (PsAF). This study investigated the impact of LA linear ablation on the complex‐fractionated atrial electrograms (CFAEs) of PsAF patients. Methods and Results: A total of 40 consecutive PsAF patients (age: 54 ± 10 years, 39 males) who underwent catheter ablation were enrolled in this study. Linear ablation of both roofline between the right and left superior PVs and the mitral isthmus line joining from the mitral annulus to the left inferior PV were performed following PV isolation during AF. High‐density automated CFAE mapping was performed using the NAVX, and maps were obtained 3 times during the procedure (prior to ablation, after PV isolation, and after linear ablations) and were compared. PsAF was terminated by ablation in 13 of 40 patients. The mean total LA surface area and baseline CFAEs area were 120.8 ± 23.6 and 88.0 ± 23.5 cm² (74.2%), respectively. After PV isolation and linear ablations in the LA, the area of CFAEs area was reduced to 71.6 ± 22.6 cm² (58.7%) (P < 0.001) and 44.9 ± 23.0 cm² (39.2%) (P < 0.001), respectively. The LA linear ablations resulted in a significant reduction of the CFAEs area percentage in the region remote from ablation sites (from 56.3 ± 20.6 cm² (59.6%) to 40.4 ± 16.5 cm² (42.9%), P < 0.0001). Conclusion: Both PV isolation and LA linear ablations diminished the CFAEs in PsAF patients, suggesting substrate modification by PV and linear ablations. (J Cardiovasc Electrophysiol, Vol. 23, pp. 962‐970, September 2012)     

Different patterns of atrial remodeling after catheter ablation of chronic atrial fibrillation

Atrial Substrate Remodeling After Chronic AF Ablation . Background: Multiple remodeling patterns have been observed after catheter ablation of atrial fibrillation (AF). Objective: We aimed to clarify the electrical/structural properties associated with recurrences after ablation of chronic AF. Methods: After a stepwise ablation procedure in 120 consecutive patients with persistent/long‐lasting persistent AF, 36 had a recurrence of AF (Group 1/Group 2: recurrence with paroxysmal/persistent AF, n = 16/20). Results: During the first procedure, the left atrial (LA) bipolar voltage did not differ between the 2 groups, and the LA volume was smaller in Group 1 than in Group 2 and it was the only factor predicting the recurrent types (P = 0.009, OR = 1.04). In the second procedure, the bipolar voltage of the global left atrium increased (1.33 ± 0.11 mV vs 1.76 ± 0.16 mV, P = 0.001) in Group 1 and decreased (1.31 ± 0.14 mV vs 0.90 ± 0.12 mV, P = 0.01) in Group 2, when compared with that of the first procedure. The LA low‐voltage area (<0.5 mV) decreased in Group 1, and increased in Group 2. The LA volume (90 ± 8 cm³ vs 72 ± 8 cm³, P = 0.002) decreased in the second procedure in Group 1. It remained the same in Group 2. The right atrial substrates did not change between the procedures. After a follow‐up of 27 ± 3 months, all patients in Group 1 and 14 patients in Group 2 remained in sinus rhythm (P = 0.02). Conclusion: A better outcome with reverse electrical and structural remodeling occurred after the ablation of chronic AF when the recurrence was paroxysmal AF. Progressive electrical remodeling without any structural remodeling developed in those with a recurrence involving persistent AF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 385‐393)     

Impact of heart rhythm status on registration accuracy of the left atrium for catheter ablation of atrial fibrillation

Introduction: Registration accuracy is of crucial importance to the successful use of image integration technique to facilitate atrial fibrillation (AF) ablation. It is well known that a patient's heart rhythm can switch from sinus rhythm (SR) to AF or vice versa during an AF ablation procedure. However, the impact of the heart rhythm change on the accuracy of left atrium (LA) registration has not been studied. Methods: This study included 10 patients who underwent AF ablation. Prior to the ablation procedure, the patients had contrast‐enhanced cardiac CT scan obtained during SR (n = 7) or AF (n = 3). Using an image integration system (CartoMerge, Biosense Webster Inc.), LA CT surface reconstruction was registered to the real‐time mapping space represented by the LA electroanatomic map. To determine the effect of rhythm change on registration accuracy, LA registration was performed during both SR and AF in each study subject. The distance between the surface of the registered LA CT reconstruction and multiple real‐time LA electroanatomic map points (surface‐to‐point distance) was used as an index for LA registration error. The position error after rhythm change was defined as the surface‐to‐point distance between the surface of the LA CT reconstruction registered in the initial rhythm and the LA electroanatomic map points sampled during the second rhythm. Results: A total of 90 ± 12 and 92 ± 9.5 LA electroanatomic map points were sampled for registration during SR and AF, respectively. No significant difference was found in surface‐to‐point distance when comparing SR with AF as the underlying rhythm during registration (1.91 ± 0.24 vs 1.84 ± 0.38 mm, P = 0.60). The position error after rhythm change was not different from the surface‐to‐point distance of LA registration conducted during the initial rhythm (2.05 ± 0.39 vs 1.96 ± 0.29 mm, P = 0.4). The surface‐to‐point distance did not differ when comparing LA registration conducted during the same versus different rhythm from that during CT imaging (1.96 ± 0.29 vs 1.79 ± 0.32 mm, P = 0.13). Conclusions: Registration error did not differ between LA registrations conducted during the same versus different rhythm as was present during CT imaging. Rhythm changes between SR and AF did not introduce significant error to the LA registration process for catheter ablation of AF. These findings are reassuring and suggest that reregistration is not needed if a patient's rhythm changes from SR to AF or vice versa during an ablation procedure.     

Investigation into Causes of Abnormal Cerebral MRI Findings Following PVAC Duty‐Cycled,Phased RF Ablation of Atrial Fibrillation

Asymptomatic Cerebral Lesions with Phased RF. Introduction: Left atrial catheter ablation of the pulmonary veins (PVs) is an established option for patients with atrial fibrillation (AF). Asymptomatic cerebral emboli (ACE) detected by diffusion weighted MRI (DW‐MRI) following AF ablation has been reported at varying rates. This variability may be linked to procedural variables and demographic risk factors. Animal studies with the multielectrode pulmonary vein ablation catheter (PVAC) have identified potential sources of emboli, including air introduced during PVAC introduction, inadequate anticoagulation, and high current densities when the distal (E1) and proximal (E10) electrodes are in contact. We sought to evaluate the incidence, size, and number of DW‐MRI findings with procedural modifications that potentially reduce the embolic load. Methods: Thirty‐seven AF patients (59 ± 10 years, 73% male, all with paroxysmal AF, left atrial [LA] diameter 44 ± 7 mm, left ventricular ejection fraction 57 ± 7%) underwent MRI sequences preceding ablation, within 24 hours postablation, and at 4–6 weeks. During the procedure all patients were on uninterrupted phenprocoumon, an attempted activated clotting time (ACT) level >300 seconds, had the PVAC introduced under saline, and antral ablation was started with a 2:1 bipolar/unipolar mode. Files from the ablation unit (GENius v14.4) were retrospectively analyzed to determine the relationship between E1 and E10 in close proximity and DW‐MRI findings. Results: Post procedure, 10/37 patients (27%) were positive for new DWI cerebral lesions. Nine of 10 patients had a single lesion, and 1/10 patient had 2 lesions. Average lesion size was 3.1 ± 3.9 mm (2–14 mm). One of 10 (10%) had lesions at MRI follow‐up. No neurological symptoms were observed. Eighteen of 37 (49%) of procedures had evidence of E1/E10 interaction. In the subgroup of patients with and without E1 and E10 in close proximity, the DW‐MRI rate was 8/18 (44%) and 2/19 (11%), respectively (P = 0.029). Conclusions: The source of positive DW‐MRI findings in LA ablation involves several factors. Controlling anticoagulation and careful sheath management helps to reduce the number and size of DW‐MRI lesions. With the PVAC catheter, an ablation with the E1 and E10 in close proximity increases the risk of a DW‐MRI finding. In the future, electrodes E1 and E10 should be kept apart to help reduce the incidence of acute ACE. (J Cardiovasc Electrophysiol, Vol. 24, pp. 121‐128, February 2013)     

Preprocedural predictors of atrial fibrillation recurrence following pulmonary vein antrum isolation in patients with paroxysmal atrial fibrillation: long-term follow-up results

Predictors of Recurrence after AF Ablation. Introduction: The objective of this study was to identify the simple preprocedural parameters of atrial fibrillation (AF) recurrence following single ablation procedure in patients with paroxysmal AF during long‐term follow‐up period. Methods and Results: Consecutive 474 patients (61 ± 10 years; 364 males, left atrial (LA) diameter 37.6 ± 5.1 mm) with drug‐refractory paroxysmal AF who underwent AF ablation were analyzed. Pulmonary vein antrum isolation (PVAI), cavotricuspid isthmus line creation with bidirectional conduction block, and elimination of all non‐PV triggers of AF were performed in all patients. With a mean follow‐up of 30 ± 13 months after single procedure, 318 patients (67.1%) were in sinus rhythm without any antiarrhythmic drugs. Multivariate analysis using Cox's proportional hazards model, including the age, gender, duration of AF, body mass index, LA size, left ventricular ejection fraction, and presence of hypertension and structural heart disease as variables, demonstrated that LA size was an independent predictor of AF recurrences after PVAI with a 7.2% increase in the probability for every 1 mm increase in LA diameter (P = 0.0007). When the patients were categorized into 3 groups according to the LA diameter, the patients with moderate (40–50 mm) and severe dilatation (>50 mm) had a 1.30‐fold (P = 0.0131) and 2.14‐fold (P = 0.0057) increase, respectively, in the probability of recurrent AF as compared with the patients with normal LA diameter (≤40 mm). Conclusion : In the long‐term follow‐up period, LA size was the best preprocedural predictor of AF recurrence following single ablation procedure in the patients with paroxysmal AF, even in the patients with a relatively small LA. (J Cardiovasc Electrophysiol, Vol. 22, pp. 621‐625, June 2011)     

Left atrial deformation imaging with ultrasound based two-dimensional speckle-tracking predicts the rate of recurrence of paroxysmal and persistent atrial fibrillation after successful ablation procedures

Predict AF. Objective: Since predictors of recurrence of atrial fibrillation (AF) after ablation procedures are poorly defined, this prospective study was conducted to assess the value of left atrial (LA) deformation imaging with two‐dimensional speckle‐tracking (2D‐ST) to predict AF recurrences after successful ablation procedures. Methods and results: One hundred and three consecutive patients (age 58.1 ± 16.6 years, 72.8% male) with AF (76 paroxysmal, 27 persistent) and 30 matched controls underwent transthoracic echocardiography and 2D‐ST‐LA‐deformation analysis with assessment of LA‐radial and LA‐longitudinal strain (Sr, Sl), and velocities derived from the apical 4‐ and 2‐chamber views (4CV, 2CV). AF recurrence was assessed during 6 months of follow‐up. For determination of AF‐related LA changes, AF patients were compared to controls and patients with AF recurrences after ablation procedures (n = 30, 29.1%) were compared with patients who maintained sinus rhythm (n = 73, 70.9%). Atrial deformation capabilities were significantly reduced (P < 0.0005) in patients with AF (4CVSl 17.8 ± 13.5%; 4CVSr 22.3 ± 14.9%; 4CV‐velocities 2.53 ± 0.97 seconds) when compared with controls (4CVSl 31.3 ± 12.4%; 4CVSr 30.3 ± 9.1%; 4CV‐velocities 3.48 ± 1.01 cm/s). Independent predictors for AF recurrence after ablation procedures were 2CV‐LA‐global‐strain (Sr, P = 0.03; Sl, P = 0.003), 4CV‐LA‐gobal‐strain (Sr, P = 0.03; Sl, P = 0.02), and regional LA‐septal wall‐Sl (P = 0.008). LA‐global‐strain parameters were superior to regional LA function analysis for the prediction of AF recurrences, with cutoff values (cov), hazard ratios (HR), positive and negative predictive values (PPV, NPV) were: 4CVSl cov, 10.79% (HR 27.8, P < 0.0005; PPV 78.8%, NPV 93.9%), 4CVSr cov, ?16.65% (HR 24.8, P < 0.0005; PPV 69.4%, NPV 96.6%), 2CVSl cov, 12.31% (HR 22.7, P < 0.0005; PPV 75.8%, NPV 95.3%), and 2CVSr cov, ?14.9% (HR 12.9, P < 0.0005; PPV 64.3%, NPV 93.2%). Conclusion: Compared with controls, AF itself seems to decrease LA deformation capabilities. The assessment of global LA strain with 2D‐ST identifies patients with high risk for AF recurrence after ablation procedures. This imaging technique may help to improve therapeutic guiding for patients with AF. (J Cardiovasc Electrophysiol, Vol. 23 p. 247‐255, March 2012.)     

Mitral Isthmus Ablation Using Steerable Sheath and High Ablation Power: A Single Center Experience

Case Series of Mitral Isthmus Ablation. Background: Mitral isthmus ablation is challenging. The use of steerable sheath and high ablation power may improve success rate. Methods: This single‐center, prospective study enrolled 200 patients who underwent ablation for atrial fibrillation (AF), including mitral isthmus ablation. Mitral isthmus ablation was performed using an irrigated ablation catheter via a steerable sheath (endocardium: maximum power: 40/50 W limited to annular end, maximum temperature: 48 °C; coronary sinus [CS]: maximum power: 25/30 W, maximum temperature: 48 °C). Endpoint was bidirectional mitral isthmus block. Results: Mitral isthmus block was acutely achieved in 182/200 patients (91%). Sixty‐nine percent of patients required CS ablation. Mean total ablation time was 13 ± 6 minutes. There was 1 case of acute circumflex artery occlusion. Mean left atrium (LA) diameter was significantly bigger in patients with unsuccessful mitral isthmus ablation (49 ± 4 mm vs. 43 ± 6 mm; P = 0.0007). In redo procedures, the incidence of reconduction at the mitral isthmus, roof and cavotricuspid isthmus was 44%, 37%, and 29%, respectively. Overall incidence of perimitral flutter was 9%. Prior complex fractionated atrial electrogram ablation was a predictor for microreentrant atrial tachycardia (AT) whereas gaps in linear lesions predicted macroreentrant flutters. After a mean follow‐up of 20 ± 9 months, 73% of patients remained free from AF or AT. Conclusion: We reported on a series of mitral isthmus ablation using steerable sheath and high ablation power (50 W). Larger LA diameter was a predictor of failure to achieve mitral isthmus block. The mitral isthmus had a moderately high incidence of re‐conduction but was only associated with a relatively low incidence of perimitral flutter. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1193–1200, November 2012)     

Randomized comparison between pulmonary vein antral isolation versus complex fractionated electrogram ablation for paroxysmal atrial fibrillation

Catheter Ablation of Paroxysmal AF. Introduction: Circumferential pulmonary vein antral isolation (PVAI) and atrial complex fractionated electrograms (CFEs) are both ablative techniques for the treatment of paroxysmal atrial fibrillation (PAF). However, data on the comparative value of these 2 ablation strategies are very limited. Methods and Results: We randomized 118 patients with drug‐refractory PAF to receive PVAI ablation (n = 60) or CFE ablation (n = 58). For CFE group, spontaneous/induced AF was mapped using validated, automated software to guide ablation until all CFE areas were eliminated. For PVAI group, all 4 pulmonary vein antra were electrically isolated as confirmed by circular mapping catheter. Patients with spontaneous/inducible AF after the initial ablation procedure were crossed over to the other arms. After initial ablation procedure, AF persisted/inducible in 24/59 patients (41%), and 34/58 patients (59%) assigned to PVAI and CFE ablation, respectively (P = 0.05). Then 58 patients underwent PVAI + CFE ablation. After 22.6 ± 6.4 months, PVAI ablation group was more likely than CFE ablation group to achieve control of any AF/atrial tachycardia (AT) off drugs (43/60, 72% vs 33/58, 57%, P = 0.075) and lower recurrence rate of AT (11.9% vs 34.5%, P = 0.004). Patients who received CFE ablation alone (38%) had significantly lower overall success rate to achieve control of AF/AT off drugs compared with patients who received PVAI ablation (77%, P = 0.002) alone or PVAI + CFE ablation (69%, P = 0.008) due to higher recurrence rate of AT (50% vs 6% vs 13%, P < 0.01). Conclusions: CFE ablation in PAF patients was associated with higher occurrence rate of postprocedure AT compared with PVAI ablation, whereby making it less likely to be a sole ablation strategy for PAF patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 973‐981, September 2011)     

Persistence of Pulmonary Vein Isolation After Robotic Remote‐Navigated Ablation for Atrial Fibrillation and its Relation to Clinical Outcome

Robotic Remote Ablation for AF . Aims: A robotic navigation system (RNS, Hansen?) has been developed as an alternative method of performing ablation for atrial fibrillation (AF). Despite the growing application of RNS‐guided pulmonary vein isolation (PVI), its consequences and mechanisms of subsequent AF recurrences are unknown. We investigated the acute procedural success and persistence of PVI over time after robotic PVI and its relation to clinical outcome. Methods and Results: Sixty‐four patients (60.7 ± 9.8 years, 53 male) with paroxysmal AF underwent robotic circumferential PVI with 3‐dimensional left atrial reconstruction (NavX?). A voluntary repeat invasive electrophysiological study was performed 3 months after ablation irrespective of clinical course. Robotic PVI was successful in all patients without complication (fluoroscopy time: 23.5 [12–34], procedure time: 180 [150–225] minutes). Fluoroscopy time demonstrated a gradual decline but was significantly reduced after the 30th patient following the introduction of additional navigation software (34 [29–45] vs 12 [9–17] minutes; P < 0.001). A repeat study at 3 months was performed in 63% of patients and revealed electrical conduction recovery in 43% of all PVs. Restudied patients without AF recurrence (n = 28) showed a significantly lower number of recovered PVs (1 (0–2) vs 2 (2–3); P = 0.006) and a longer LA‐PV conduction delay than patients with AF recurrences (n = 12). Persistent block of all PVs was associated with freedom from AF in all patients. At 3 months, 67% of patients were free of AF, while reablation of recovered PVs led to an overall freedom from AF in 81% of patients after 1 year. Conclusion: Robotic PVI for PAF is safe, effective, and requires limited fluoroscopy while yielding comparable success rates to conventional ablation approaches with PV reconduction as a common phenomenon associated with AF recurrences. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1079‐1084)     

Long‐Term Outcome of Atrial Fibrillation Ablation: Impact and Predictors of Very Late Recurrence

Long‐Term Outcome of AF Ablation. Introduction: Ablation eliminates atrial fibrillation (AF) in studies with 1 year follow‐up, but very late recurrences may compromise long‐term efficacy. In a large cohort, we sought to describe the determinants of delayed recurrence after AF ablation. Methods and Results: Seven hundred and seventy‐four patients with AF (428 paroxysmal [PAF, 55%] and 346 persistent or longstanding persistent [PersAF, 45%]) underwent wide area circumferential ablation (WACA, 62%) or pulmonary vein isolation (38%). Over 3.0 ± 1.9 years, there were 135 recurrences in PAF patients and 142 in PersAF patients. AF elimination was achieved in 61% of patients with PersAF at 2 years after last ablation and in 71% of patients with PAF (P = 0.04). This finding was related to a higher initial rate of very late recurrence in PersAF. From 1.0 to 2.5 years, the recurrence increased by 20% (from 37% to 57%) in PersAF patients versus only 12% (from 27% to 39%) in PAF patients. Independent predictors of overall recurrence included diabetes (HR 1.9 [1.3–2.9], P = 0.002) and PersAF (HR 1.6 [1.2–2.0], P < 0.001). Independent predictors of very late recurrence included PersAF (HR 1.7 [1.1–2.7], P = 0.018) and WACA (HR 1.8 [1.1–2.7], P = 0.018), while diabetes came close to significance. In PAF patients, left atrial size >45 mm was identified as an AF‐type specific predictor (HR 2.4 [1.3–4.7], P = 0.009), whereas in PersAF patients, no unique predictors were identified. Conclusion: Late recurrences reduced the long‐term efficacy of AF ablation, particularly in patients with PersAF and underlying cardiovascular diseases. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1071‐1078)     

Prospective assessment of short- and long-term quality of life after ablation for atrial fibrillation

Quality of Life After Ablation for Atrial Fibrillation. Background : This study prospectively assesses different aspects of short‐ and long‐term quality of life (QoL) after catheter ablation for atrial fibrillation (AF). An analysis of 7 validated generic and tailored questionnaires was performed with regard to the relation of QoL to ablation success. Methods : The study included 133 patients (74% men, age 57±10) who underwent pulmonary vein isolation ± linear or electrogram‐guided substrate modification for AF. QoL was quantitatively assessed at baseline, 3 months after ablation and at a median of 4.3 ± 0.5 years after ablation by the AF severity scale (AFSS), AF symptom checklist (AFSC), WHO‐5‐Well‐Being‐Index (WHO), Major Depression Inventory (MDI), Sleep and Vegetative disorder (SV), Vital Exhaustion (VE), and Illness intrusiveness (Ii). Results: QoL was improved significantly 3 months after ablation in all patients (regardless of ablation success or AF type) and stayed significantly improved after a median of 4.3±0.5 years (AFSS, AFSC, WHO, MDI, VE, PE (all P < 0.001), and SV (P = 0.007)). Patients who had a successful ablation improved significantly more than patients with an unsuccessful ablation in the AFSS, AFSC, and MDI questionnaire (delta change from baseline to long‐term follow‐up P = <0.001, P = <0.001, and P = 0.039, respectively). Conclusion: Overall, all patients significantly improved their QoL irrespective of the AF type in all questionnaires 3 months and 4 years after ablation. The increase in QoL was significantly greater in patients who underwent a successful ablation than patients with unsuccessful ablation in the AFSS, AFSC, and MDI questionnaire. Cardiovasc Electrophysiol, Vol. 23, pp. 121‐127, February 2012)     

Reversal of left ventricular dysfunction following ablation of atrial fibrillation

Background: Evaluation of ventricular rate control in atrial fibrillation (AF) can be difficult, and the presence of an AF‐induced ventricular cardiomyopathy due to intermittent poor rate control or other causes may be underestimated. The outcome with AF ablation in patients with a decreased left ventricular ejection fraction (LVEF) may provide insight into this important clinical issue. Objective: To determine the effect of pulmonary vein isolation on LVEF in patients with AF and decreased LVEF (≤50%). Methods: Ablation consisted of proximal isolation of arrhythmogenic pulmonary veins (PVs) and elimination of non‐PV triggers. LVEF was determined within 24 hours after ablation and again at up to 6 months follow‐up. Transtelephonic monitoring was performed routinely for 2–3 weeks prior to ablation, at 6 weeks, and 6 months post and with symptoms following ablation. AF control was defined as freedom from AF or marked (>90%) reduction in AF burden on or off previously ineffective antiarrhythmic medication. Results: AF ablation was performed in 366 patients and 67 (18%) patients had decreased LV function with a mean LVEF of 42 ± 9%. An average of 3.4 ± 0.9 PVs were isolated. AF control in the depressed LVEF group compared favorably with the normal EF group (86% vs. 87% P = NS), although more redo procedures were required (1.6 ± 0.8 vs 1.3 ± 0.6 procedures; P ≤ 0.05). Only 15 of 67 patients (22%) with decreased LVEF had shown tachycardia (>100 bpm) on repeated preablation ECG recordings during AF. In the decreased LVEF group, the LVEF increased from 42 ± 9% to 56 ± 8% (P < 0.001) after ablation. Conclusions: Patients with AF and decreased LVEF undergoing AF ablation have similar success to patients with normal LVEF and have improvement in LVEF after ablation. These results suggest the presence of a reversible AF‐induced ventricular cardiomyopathy in many patients with AF and depressed LV function. The presence of under‐recognized and reversible cardiomyopathy even when tachycardia is not persistent is important to recognize.