Pulmonary vein isolation and left atrial catheter ablation using a three-dimensional navigation system for the treatment of atrial fibrillation

BACKGROUND:

Atrial fibrillation (AF) is often triggered by ectopic foci originating from pulmonary veins (PVs), with the posterior left atrium (LA) comprising part of the substrate for maintenance. Catheter ablation strategies targeting PVs and the posterior LA may be further refined by incorporating technology beyond standard fluoroscopy.

OBJECTIVES:

To prospectively assess the usefulness of a navigation system to guide a radiofrequency catheter ablation strategy, combining PV isolation (PVI) with anatomical LA ablation.

METHODS:

Sixty-four patients (51 men; mean [± SD] age 52±8 years) who were referred for catheter ablation of paroxysmal (n=49) or persistent (n=15) AF underwent this ablation strategy using the NavX system (Endocardial Solutions Inc, USA). Electrical PVI was guided by a circular mapping catheter. Anatomical ablation consisted of lines drawn along the posterior aspect of the LA from the superior PVs to the inferior PVs. NavX was used for the construction of three-dimensional LA and PV maps with projection of mapping and ablation catheters on the image in real time and for tracking of lesions during posterior LA ablation.

RESULTS:

Electrical PVI was achieved in 100% of procedures and all patients underwent the linear posterior LA ablation described above. Procedural and fluoroscopy times were 188±41 min and 60±12 min, respectively. Repeat procedures for AF recurrence were required in 38 (59%) patients. After a mean follow-up period of 16±10 months, 59 (92%) patients remained arrhythmia-free, including 52 (81%) without antiarrhythmic drugs.

CONCLUSIONS:

An AF ablation strategy that combines nonfluoroscopic visualization of catheters with electrical PVI and anatomical LA ablation is feasible, safe and effective, but often requires repeat procedures.     

Study Design of the Man and Machine Trial: A Prospective International Controlled Noninferiority Trial Comparing Manual with Robotic Catheter Ablation for Treatment of Atrial Fibrillation

Study Design of the Man and Machine Trial. Background: Pulmonary vein isolation (PVI) has become the cornerstone procedure for the treatment of symptomatic drug‐resistant atrial fibrillation (AF). At the present time, circumferential PVI (CPVI) using irrigated radiofrequency (RF) is the mostly used ablation technique. However, for CPVI, precise catheter navigation and excellent catheter stability is crucial thereby requiring experienced operators. Robotic navigation systems have been introduced to facilitate catheter navigation and to improve catheter stability, therefore potentially increasing procedural success and making CPVI accessible to less experienced operators. To date, no prospective randomized trial has evaluated the efficacy and safety of CPVI using RNS compared to manually performed ablation. Methods: In this prospective international multicenter noninferiority trial, 258 patients with either paroxysmal or short‐standing persistent AF will be randomized for comparison of PVI using either manual or robotic ablation. In all patients, CPVI will be performed using irrigated RF ablation in combination with a 3D mapping system. The primary endpoint of the trial is the absence of AF or atrial tachycardia without antiarrhythmic drug therapy during 12‐month follow‐up. Secondary endpoints will be evaluation of periprocedural complications and procedural data such as procedure time, fluoroscopy time, as well as the incidence of esophageal injury assessed by endoscopy within 48 hours after the procedure. Conclusion: The “Man and Machine Trial” is the first prospective international randomized controlled multicenter noninferiority trial to compare manually performed CPVI with robotically navigated CPVI, evaluating both the safety and efficacy of the 2 techniques during a 12‐month follow‐up period. (J Cardiovasc Electrophysiol, Vol. 24, pp. 40‐46, January 2013)     

CMR-Guided Approach to Localize and Ablate Gaps in Repeat AF Ablation Procedure

ObjectivesThe aim of this study was to test the feasibility and usefulness of a new delayed-enhancement cardiac magnetic resonance (DE-CMR)–guided approach to ablate gaps in redo procedures.BackgroundRecurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI) may be related to gaps at the ablation lines. DE-CMR allows identification of radiofrequency lesions and gaps (CMR gaps).MethodsFifteen patients undergoing repeated AF ablations were included (prior procedure was PVI in all patients and roof-line ablation in 8 patients). Pre-procedure 3-dimensional (3D) DE-CMR was performed with a respiratory-navigated (free-breathing) and electrocardiographically gated inversion-recovery gradient-echo sequence (voxel size 1.25 × 1.25 × 2.5 mm). Endocardium and epicardium were manually segmented to create a 3D reconstruction (DE-CMR model). A pixel signal intensity map was projected on the DE-CMR model and color-coded (thresholds 40 ± 5% and 60 ± 5% of maximum intensity). The DE-CMR model was imported into the navigation system to guide the ablation of CMR gaps, with the operator blinded to electrical data. Fifteen conventional procedures were used as controls to compare procedural duration, radiofrequency, and fluoroscopy times.ResultsFifteen patients (56 pulmonary veins [PVs]; 57 ± 8 years of age; 9 with paroxysmal AF) were analyzed. In total, 67 CMR gaps were identified around PVs (mean 4.47 gaps/patient; median length 13.33 mm/gap) and 9 at roof line. All of the electrically reconnected PVs (87.5%) had CMR gaps. The site of electrical PV reconnection (assessed by circular mapping catheter) matched with a CMR gap in 79% of PVs. CMR-guided ablation led to reisolation of 95.6% of reconnected PVs (median radiofrequency time of 13.3 [interquartile range: 7.5 to 21.7] min/patient) and conduction block through the roof line in all patients (1.4 [interquartile range: 0.7 to 3.1] min/patient). Compared with controls, the CMR-guided approach shortened radiofrequency time (1,441 ± 915 s vs. 930 ± 662 s; p = 0.026) but not the procedural duration or fluoroscopy time.ConclusionsDE-CMR can successfully guide repeated PVI procedures by accurately identifying and localizing gaps and may reduce procedural duration and radiofrequency application time.     

Ablation of Atrial Fibrillation Utilizing Robotic Catheter Navigation in Comparison to Manual Navigation and Ablation: Single‐Center Experience

Background: Robotic catheter navigation and ablation either with magnetic catheter driving or with electromechanical guidance have emerged in the recent years for the treatment of atrial fibrillation. Objective: The aim of this study was to compare our center's experience of atrial fibrillation ablation using the Hansen Robotic Medical System with our current manual ablation technique in terms of acute and chronic success, as well as procedure time and radiation exposure to both the patient and the operator. Methods: A total of 390 consecutive patients with symptomatic and drug‐resistant atrial fibrillation (289 males, 62 ± 11 years) were prospectively enrolled in the study. All patients underwent the procedure either with conventional manual ablation (group 1, n = 197) or with the robotic navigation system (RNS) (group 2, n = 193). Results: The success rate for RNS was 85% (164 patients), while for manual ablation it was 81% (159 patients) (p = 0.264) at 14.1 ± 1.3 months with AADs previously ineffective. Fluoroscopy time was significantly lower for RNS (48.9 ± 24.6 minutes for RNS vs. 58.4 ± 20.1 minutes for manual ablation, P < 0.001). Mean fluoroscopy time was statistically reduced after 50 procedures (61.8 ± 23.2 minutes for first 50 cases vs. 44.5 ± 23.6 minutes for subsequent procedures, P < 0.0001). Conclusion: Robotic navigation and ablation of atrial fibrillation is safe and effective. Fluoroscopy time decreases with experience.     

Impact of Radiofrequency Characteristics on Acute Pulmonary Vein Reconnection and Clinical Outcome After PVAC Ablation

Impact of Radiofrequency Characteristics . Objective: The objective was to study the impact of radiofrequency (RF) characteristics on acute pulmonary vein reconnection (PVR) and outcome after PVAC ablation. PVI with additional ablation of PVR (PVI + PVR) was compared to PVI‐only. Methods: In 40 consecutive patients, after PVAC‐guided PVI, adenosine and a 1‐hour waiting time were used to unmask and ablate acute PVR (PVI + PVR group). RF‐characteristics and 1‐year AF freedom were compared post hoc to 40 clinically matched patients undergoing PVI only (PVI‐only group). Custom‐made software was used to assess RF characteristics of the PVAC applications needed to obtain baseline PVI. Results: There was no difference in clinical characteristics or baseline RF‐profile between both groups. Acute PVR was observed and ablated in 38 of 160 veins (24%). AF‐freedom after PVI + PVR was higher than PVI (85% vs 65%, P < 0.05). Within the PVI group, comparing patients with and without AF‐recurrence, the percentage of PVAC applications with high T° (>48°) but low power (<3W) was higher (28 ± 18% vs 11 ± 11%, P < 0.0001). Within the PVI + PVR group, when comparing PVs with and without PVR, the percentage of low power/high T° PVAC applications was also higher (27 ± 13% vs 13 ± 15%, P < 0.0001). Conclusions: (1) After PVAC ablation, 24% of PVs exhibit acute reconnection. Additional ablation of reconnection improves clinical outcome. (2) Acute reconnection as well as clinical recurrence of AF are characterized by PVAC ablation with a considerable number of applications with high temperature but low power. (3) If PV isolation is obtained with low power applications, a consistent use of both adenosine and waiting time is required. (J Cardiovasc Electrophysiol, Vol. 24, pp. 290‐296, March 2013)     

A Prospective,Randomized Comparison of Modified Pulmonary Vein Isolation Versus Conventional Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation

Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012)     

Pulmonary Vein Contraction Before and After Radiofrequency Ablation for Atrial Fibrillation

Pulmonary Vein Contraction After Ablation. Introduction: Cardiovascular magnetic resonance imaging (cMRI) may provide a noninvasive method to test for pulmonary vein (PV) isolation after ablation for atrial fibrillation (AF) by detecting changes in PV contraction. Methods: PV contraction (the maximal percentage change in PV cross‐sectional area [CSA] during the cardiac cycle) measured 1 month before and 2 months after PV isolation was compared in 63 PVs from 16 patients with medically refractory AF. Repeat cMRI imaging and invasive catheter mapping was performed prior to repeat PV ablation in 50 PVs from 14 additional patients with recurrent AF. Contraction in PVs with sustained isolation after the initial ablation was compared to contraction in PVs with electrical reconnection to adjacent atrium. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff PV contraction value for prediction of PV‐atrial reconnection after ablation. The cutoff value was then prospectively tested in 40 PVs from 12 additional patients. Results: PV contraction decreased after AF ablation (22.4 ± 10% variation in CSA before ablation vs 10.1 ± 8% variation in CSA after ablation, P < 0.00001). PVs with sustained isolation on invasive mapping contracted less than PVs with electrical reconnection to adjacent atrium (13.7 ± 10.6% vs 21.4 ± 9.3%, P = 0.021). PV contraction produced a c‐index of 0.74 for prediction of PV‐atrial reconnection after ablation and >17% variation in PV CSA predicted reconnection with a sensitivity of 84.6% and specificity of 66.7%. Conclusion: PV contraction is reduced by ablation. PV contraction measurement may provide a noninvasive method to test for PV isolation after ablation procedures. (J Cardiovasc Electrophysiol, Vol. 22, pp. 169‐174, February 2011)     

Acute and Long‐Term Clinical Outcome After Endoscopic Pulmonary Vein Isolation: Results from the First Prospective,Multicenter Study

Clinical Outcome After Endoscopic PVI. Introduction: The acute and long‐term outcome of pulmonary vein isolation (PVI) using an endoscopic ablation system (EAS) has only been reported in single‐center studies. The current prospective, multicenter study assessed the acute and 1‐year outcome following PVI using the EAS. Methods and Results: Seventy‐two patients (34 female, mean age 58 ± 10 years) with a history (5 ± 6 years) of drug‐refractory paroxysmal atrial fibrillation (AF) were included. Endoscopic PVI was performed in all patients. Follow‐up was based on regular telephone interviews, Holter ECG, and transtelephonic ECG recordings. Recurrence was defined as a symptomatic and/or documented AF episode >30 seconds following a blanking period of 3 months. In 72 patients, a total of 281 pulmonary veins (PVs) were targeted and 277/281 (98.6%) PVs were isolated successfully using only the EAS. PV stenosis, thrombembolic events, pericardial effusion, pericardial tamponade, and phrenic nerve palsy occurred in 0 of 72, 0 of 72, 3 of 72 (4.2%), 4 of 72 (5.6%), and in 1 of 72 (1.4%) patients, respectively. Sixty‐seven of 72 (93.1%) patients completed a follow‐up of 365 days and 42 of 67 (62.7%) patients remained in stable sinus rhythm after a single procedure. A total of 13 of 25 (52%) patients suffering from AF recurrence consented to repeat PVI using conventional radiofrequency energy 221 ± 121 days after the index procedure. LA to PV reconduction was found in 30 of 45 (67%) previously isolated PVs. Conclusions: A very high rate of acute electrical PVI is achieved using exclusively the EAS. The 1‐year single‐procedure success rate in patients with paroxysmal AF is comparable to conventional PVI. PV reconduction is the major determinant for AF recurrence. (J Cardiovasc Electrophysiol, Vol. 24, pp. 7‐13, January 2013)     

The effects of standard electrical PV isolation vs. “pace and ablate” on ATP-provoked PV reconnections

Background

Catheter ablation procedures for atrial fibrillation (AF) often involve circumferential pulmonary vein isolation (PVI). Lack of reliable identification of conduction gaps along the ablation line necessitates additional ablation within previous lesion sets. We conducted a retrospective comparative study to determine the best PVI strategy for prevention of PV reconnections.

Methods and results

We compared the outcomes of PVI performed in two groups of patients with AF: those in whom a three-dimensional mapping system and irrigated tip radiofrequency catheter were used to electrically isolate the ipsilateral PVs (31 patients, electrical isolation group) and those in whom “pace and ablate” was performed in the PV antra until pacing at 10 mA and 2 ms no longer captured the atrial myocardium along the ablation line (31 patients, pace and ablate group). A bolus administration of 30 mg of adenosine triphosphate (ATP) revealed dormant PV reconnections more frequently in the electrical isolation group than in the pace and ablate group (28 [90 %] of 31 patients vs. 16 [52 %] of 31 patients, p?=?0.0005). After re-isolation of the sites of dormant PV conduction, the post-ablation recurrence rates at 1 year were similar (26 vs. 26 %, p?=?1.000).

Conclusion

Electrical PVI can usually be achieved without complete circumferential ablation. However, the isolated PVs often show dormant conduction. These findings support the hypothesis that reversible tissue injury contributes to PVI that may be acute but not necessarily durable. Similar outcomes between the two ablation strategies suggest that ATP provocation tests remain necessary to unmask dormant PV conduction.     

Recurrence of paroxysmal atrial fibrillation after cryoisolation of the pulmonary veins. Is a “redo” procedure using the cryoballoon useful?

Background

Pulmonary vein (PV) isolation with the cryoballoon technique is an effective and safe method to treat patients with paroxysmal atrial fibrillation (AF). However, the optimal treatment strategy for patients with recurrences after this ablation is unclear.

Aims

The aim of this single centre study was to evaluate the efficacy and safety of a “redo” procedure using the cryoballoon in this patient cohort. The secondary study objectives were to determine the rate of reconduction for individual PVs of the patients undergoing “redo” ablation and potential predictors of persistent PV isolation (PVI).

Methods

Between April 2006 and September 2009, all patients with paroxysmal AF recurrences after cryoballoon ablation a “redo” ablation with the cryoballoon was offered. PV conduction was determined and cryoapplications were performed in all reconnected PVs. Every 3 months, 7-day Holter ECG, symptom-driven transtelephonic ECG recordings, and questionnaires were collected for 12 months.

Results

Forty-seven patients underwent “redo” cryoballoon ablation. In all these patients, at least one PV with reconduction was found. Recurrent conduction was documented in 63 % of the left superior PV, 56 % of the left inferior PV, 43 % of the right superior PV, and 56 % of the right inferior PV. In 28 of the 47 patients (60 %), no AF recurrence was detectable during the 12-month follow-up (after 3 months blanking period). Rate of severe complications was low and not significantly different from that of the initial ablations.

Conclusion

“Redo” ablation using cryoballoon technology may be an effective and safe method to treat patients with recurrence of paroxysmal AF after cryoballoon PVI.     

Cryoballoon Versus Radiofrequency for Pulmonary Vein Re‐Isolation After a Failed Initial Ablation Procedure in Patients with Paroxysmal Atrial Fibrillation

Cryoballoon versus Radiofrequency Ablation . Aim: Catheter ablation of paroxysmal atrial fibrillation (PAF) is associated with an important risk of early and late recurrence, necessitating repeat ablation procedures. The aim of this prospective randomized patient‐blind study was to compare the efficacy and safety of cryoballoon (Cryo) versus radiofrequency (RF) ablation of PAF after failed initial RF ablation procedure. Methods: Patients with a history of symptomatic PAF after a previous failed first RF ablation procedure were eligible for this study. Patients were randomized to Cryo or RF redo ablation. The primary endpoint of the study was recurrence of atrial tachyarrhythmia, including AF and left atrial flutter/tachycardia, after a second ablation procedure at 1 year of follow‐up. All patients were implanted with a cardiac monitor (Reveal XT, Medtronic) to continuously track the cardiac rhythm. Patients with an AF burden (AF%) ≤ 0.5% were considered AF‐free (Responders), while those with an AF% > 0.5% were classified as patients with AF recurrences (non‐Responders). Results: Eighty patients with AF recurrences after a first RF pulmonary vein isolation (PVI) were randomized to Cryo (N = 40) or to RF (N = 40). Electrical potentials were recorded in 77 mapped PVs (1.9 ± 0.8 per patient) in Cryo Group and 72 PVs (1.7 ± 0.8 per patient) in RF Group (P = 0.62), all of which were targeted. In Cryo group, 68 (88%) of the 77 PVs were re‐isolated using only Cryo technique; the remaining 9 PVs were re‐isolated using RF. In RF group, all 72 PVs were successfully re‐isolated (P = 0.003 vs Cryo). By intention‐to‐treat, 23 (58%) RF patients were AF‐free vs 17 (43%) Cryo patients on no antiarrhythmic drugs at 1 year (P = 0.06). Three patients had temporary phrenic nerve paralysis in the Cryo group; the RF group had no complications. Of the 29 patients who had only Cryo PVI without any RF ablation, 11 (38%) were AF‐free vs 20 (59%) of the 34 patients who had RF only (P = 0.021). Conclusion: When patients require a redo pulmonary vein isolation ablation procedure for recurrent PAF, RF appears to be the preferred energy source relative to Cryo. (J Cardiovasc Electrophysiol, Vol. 24, pp. 274‐279, March 2013)     

Anatomical Predictors for Acute and Mid‐Term Success of Cryoballoon Ablation of Atrial Fibrillation Using the 28 mm Balloon

Anatomical Predictors for Acute and Mid‐Term Success of Cryoballoon Ablation. Introduction: Cryoballoon (CB) pulmonary vein isolation (CB‐PVI) for the treatment of paroxysmal atrial fibrillation (AF) has been demonstrated to be safe and reliable. Preprocedural patient selection to address the high variability in pulmonary vein (PV) anatomy may improve the acute and chronic success of CB‐PVI. The purpose of this study was to identify anatomical predictors for CB‐PVI failure using the 28 mm balloon. Methods and Results : We included 47 patients with paroxysmal AF undergoing CB‐PVI with the 28 mm CB. Anatomical global left atrial and PV selective parameters were quantified from 3‐dimensional reconstructed preprocedural computed tomography or magnetic resonance imaging data. The mean follow‐up was 26 ± 9 months (range: 12–32 months). Multivariate logistic regression analysis revealed that a continuous sharp left lateral ridge between the left PVs and the left lateral appendage (OR, 7.09; 95% CI, 1.17–43.47) and a sharp carina between the left superior and left inferior PV (OR, 5.99; 95% CI, 1.33–27.03) predict acute and mid‐term failure. For the right inferior PVs, a non‐perpendicular angle between the axis of the PV and the ostial plane (OR, 6.33; 95% CI, 1.20–33.33) and an early branching PV with change in the axis angle (OR, 7.41; 95% CI, 1.44–38.46) were predictors of acute and mid‐term failure. Conclusion: Anatomical variables preventing maximal heat transfer from the tissue to the CB could be identified as predictors for CB‐PVI failure with the 28 mm balloon. These findings may be a step toward a more tailored ablation strategy based on individual anatomical variations. (J Cardiovasc Electrophysiol, Vol. 24, pp. 132‐138, February 2013)     

Reduced Fluoroscopy During Atrial Fibrillation Ablation: Benefits of Robotic Guided Navigation

Reduced Fluoroscopy in PVI Using RN.   Background: Recently, a nonmagnetic robotic navigation system (RN, Hansen-Sensei™) has been introduced for remote catheter manipulation.
Objective: To investigate the influence of RN combined with intuitive 3-dimensional mapping on the fluoroscopy exposure to operator and patient during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) in a prospective randomized trial.
Methods: Sixty patients were randomly assigned to undergo PVI either using a RN guided (group 1; n = 30, 20 male, 62 ± 7.7 years) or conventional ablation approach (group 2; n = 30, 14 male, 61 ± 7.6 years). A 3-dimensional mapping system (NavX™) was used in both groups.
Results: Electrical disconnection of the ipsilateral pulmonary veins (PVs) was achieved in all patients. Use of RN significantly lowered the overall fluoroscopy time (9 ± 3.4 vs 22 ± 6.5 minutes; P < 0.001) and reduced the operator's fluoroscopy exposure (7 ± 2.1 vs 22 ± 6.5 minutes; P < 0.001). The difference in fluoroscopy duration between both groups was most pronounced during the ablation part of the procedure (3 ± 2.4 vs 17 ± 6.3 minutes; P < 0.001). The overall procedure duration tended to be prolonged using RN without reaching statistical significance (156 ± 44.4 vs 134 ± 12 minutes, P = 0.099). No difference regarding outcome was found during a midterm follow-up of 6 months (AF freedom group 1 = 73% vs 77% in group 2 [P = 0.345]).
Conclusion: The use of RN for PVI seems to be effective and significantly reduces overall fluoroscopy time and operator's fluoroscopy exposure without affecting mid-term outcome after 6-month follow-up. (J Cardiovasc Electrophysiol, Vol. 21, pp. 6–12, January 2010)     

Robotic magnetic navigation-guided catheter ablation establishes highly effective pulmonary vein isolation in patients with paroxysmal atrial fibrillation when compared to conventional ablation techniques

Introduction

Pulmonary vein isolation (PVI) is a pivotal part of ablative therapy for atrial fibrillation (AF). Currently, there are multiple techniques available to realize PVI, including: manual-guided cryoballoon (MAN-CB), manual-guided radiofrequency (MAN-RF), and robotic magnetic navigation-guided radiofrequency ablation (RMN-RF). There is a lack of large prospective trials comparing contemporary RMN-RF with the more conventional ablation techniques. This study prospectively compared three catheter ablation techniques as treatment of paroxysmal AF.

Methods

This multicenter, prospective study included patients with paroxysmal AF who underwent their first ablation procedure. Procedural parameters (including procedural efficiency), complication rates, and freedom of AF during 12-month follow-up, were compared between three study groups which were defined by the utilized ablation technique.

Results

A total of 221 patients were included in this study. Total procedure time was significantly shorter in MAN-CB (78 ± 21 min) compared to MAN-RF (115 ± 41 min; p < .001) and compared to RMN-RF (129 ± 32 min; p < .001), whereas it was comparable between the two radiofrequency (RF) groups (p = .062). A 3% complication rate was observed, which was comparable between all groups. At 12-month follow-up, AF recurrence was observed in 40 patients (19%) and was significantly lower in the robotic group (MAN-CB 19 [24%], MAN-RF 16 [23%], RMN-RF 5 [8%] AF recurrences, p = .045) (multivariate hazard ratio of RMN-RF on AF recurrence 0.32, 95% confidence interval: 0.12–0.87, p = .026).

Conclusion

RMN-guided PVI results in high freedom of AF in patients with paroxysmal AF, when compared to cryoablation and manual RF ablation. Cryoablation remains the most time-efficient ablation technique, whereas RMN nowadays has comparable efficiency with manual RF ablation.     

Reduction of fluoroscopy exposure and procedure duration during ablation of atrial fibrillation using a novel anatomical navigation system.

AIMS: Catheter ablation of atrial fibrillation (AF) is centred on pulmonary vein (PV) ablation with or without additional atrial substrate modification. These procedures may be prolonged with significant fluoroscopy exposure. This study evaluates a new non-fluoroscopic navigation system during ablation of AF. METHODS AND RESULTS: Seventy-two patients undergoing catheter ablation of symptomatic drug refractory AF were prospectively randomized to ablation with (n=35; study group) or without (n=37; control group) non-fluoroscopic navigation. PV isolation was performed in all patients. In patients with persistent or inducible sustained AF after PV isolation linear ablation was performed by joining the superior PVs. PV isolation was achieved in all patients; fluoroscopy (15.4+/-3.4 vs. 21.3+/-6.4 min; P<0.001) and procedural (52+/-12 vs. 61+/-17 min; P=0.02) durations were significantly reduced in the study group. Linear block was achieved in 37 of the 39 patients; with a significant reduction in fluoroscopy (5.6+/-2.2 vs. 9.9+/-4.8 min; P=0.003) and procedural (14.7+/-5.5 vs. 26.6+/-16.9 min; P=0.007) durations in the study group. After a follow-up of 6.9+/-2.9 months (range 3-10), 26 (74%) patients in the non-fluoroscopic navigation group and 29 (78%) patients in the control group were arrhythmia-free after the first procedure. CONCLUSION: This prospectively randomized study demonstrates significant reduction of fluoroscopy exposure and procedural duration using supplementary non-fluoroscopic imaging system for AF ablation.     

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)     

Pulmonary Vein Isolation Supported by MRI‐Derived 3D‐Augmented Biplane Fluoroscopy: A Feasibility Study and a Quantitative Analysis of the Accuracy of the Technique

MRI‐Derived 3D‐Augmented Biplane Fluoroscopy . Background: Despite the advancement of technology in electroanatomic mapping systems (EAMS), fluoroscopy remains a necessary, basic imaging modality for electrophysiology procedures. We present a feasibility study of new software that enables 3D‐augmented fluoroscopy in biplane catheterization laboratories for planning and guidance of pulmonary vein isolation (PVI). The computer‐assisted overlay registration accuracy was assessed in a clinical setting using an automatic calculation of overlay projection geometry that was derived from hardware sensors in C‐arms, detectors, and patient table. Methods: Consecutive patients (n = 89) underwent left atrium (LA) magnetic resonance imaging MRI scan prior to PVI. Ideal ablation lines encircling the ipsilateral pulmonary veins (PVs) at antral level were drawn onto the segmented LA surface. The 3D‐model was superimposed onto biplane fluoroscopy and matched with angiographies of LA and PVs. Three‐dimensional‐overlay projection geometry was automatically calculated from C‐arm, detectors, and table sensors. Accuracy of technique was assessed as alignment of MRI‐derived 3D overlay and angiographic LA/PV anatomy. Integrity of registered overlay was quantified using landmark measurements. Results: Alignment offsets were 1.3 ± 1.5 mm in left PV, 1.2 ± 1.5 mm in right PV, and 1.1 ± 1.4 mm in LA roof region. Bravais–Pearson correlation of the landmark measurements was r = 0.978 (s  < 0.01), mean offset between landmark distance measurements was 1.4 ± 0.78 mm. Average time needed for overlay registration was 9.5 ± 3.5 seconds. Conclusions: MRI‐derived 3D‐augmented fluoroscopy demonstrated a high level of accuracy when compared with LA/PV angiography. The new system could be especially useful to guide procedures not supported by EAMS, such as cryotechnique PVI. (J Cardiovasc Electrophysiol, Vol. 24, pp. 113‐120, February 2013)     

Incidence and location of focal atrial fibrillation triggers in patients undergoing repeat pulmonary vein isolation: implications for ablation strategies

INTRODUCTION: The etiology of atrial fibrillation (AF) recurrences after pulmonary vein (PV) isolation is not well described. The aim of this study was to examine the reason for recurrent AF in patients undergoing a repeat attempt at AF trigger ablation. METHODS AND RESULTS: Patients with recurrent AF more than 1 month after ablation returned for repeat mapping and ablation. A circular mapping catheter was advanced to each previously targeted PV ostium to determine if the PV was still electrically isolated. Ectopy then was provoked with isoproterenol (up to 20 microg/min), burst pacing, and pacing into AF followed by cardioversion. The location of ectopy triggering atrial premature depolarizations (APDs) or AF was noted. Of 226 patients who underwent ablation of AF triggers, 34 (8 women and 26 men; age 56 +/- 10 years) with recurrent AF returned for a repeat procedure 207 +/- 183 days after the first procedure. There were 84 previously completely isolated PVs in these 34 patients. Thirty-three (39%) of 84 previously isolated PVs were still completely isolated at the time of the second procedure. Fifty-one PVs (61%) had evidence of recovered PV potentials. Fifty triggers of APDs and AF (n = 30) or APDs only (n = 20) were identified in these 34 patients. The majority of triggers [27/50 (54%)] originated from previously targeted PVs. Sixteen triggers [16/50 (32%)] originated from previously nontargeted PVs. CONCLUSION: The majority of AF recurrences originate from previously isolated PVs. One third of recurrent triggers originated from PVs that were not targeted during the initial ablation session. Although empiric isolation of all PVs may reduce recurrences, strategies to ensure ostial PV isolation and to prevent recurrent PV conduction after ablation should have the greatest impact on reducing AF recurrence.     

Visually guided sequential pulmonary vein isolation: insights into techniques and predictors of acute success

Sequential PVI with Laser Balloon . Introduction: Pulmonary vein isolation (PVI) is a challenging procedure most often requiring sophisticated technical aids such as electroanatomical mapping, double transseptal access, and the use of a circular mapping catheter. We sought to develop a PVI strategy solely based on visual guidance with a single ablation device as well as a single transseptal puncture using the endoscopic ablation system (EAS). Methods and Results: In 35 patients with drug‐refractory atrial fibrillation (18 male, mean age: 62 ± 9 years) ablation was performed. PVI was achieved in 96 of 137 PVs (70%) purely by visually guided circular ablation. Predictors of acute isolation were the degree of PV occlusion by EAS as well as the number of catheter repositionings but not total ablation energy or the number of laser applications. Conduction gaps were detected at sites with suboptimal occlusion as well as esophageal temperature elevations. Further EAS ablation resulted in a 98% acute isolation rate. Mean procedure and fluoroscopy times were 154 ± 38 minutes and 16 ± 6 minutes, respectively. Between the first and last 12 cases, a reduction in procedure times (175 ± 48 minutes vs 138 ± 26 minutes; P = 0.05) was observed. One pericardial tamponade and 1 right‐sided phrenic nerve palsy occurred. During a median follow‐up of 266 days (q‐q3: 218–389), 27 of 35 patients (77%) remained free of any tachyarrhythmia recurrence off antiarrhythmic drugs. Conclusions: Sequential PVI based solely on endoscopic visual information with a single device and a single transseptal puncture is feasible. Optimal PV occlusion and few controlled repositionings facilitate PVI. (J Cardiovasc Electrophysiol, Vol. 23, pp. 576–582, June 2012)     

Ablation of Atrial Fibrillation at the Time of Cavotricuspid Isthmus Ablation in Patients With Atrial Flutter Without Documented Atrial Fibrillation Derives a Better Long‐Term Benefit

AF Ablation in Patients With Only Documentation of Atrial Flutter. Objectives: The aim of the study was to evaluate whether isolation of the pulmonary veins (PVs) at the time of cavotricuspid isthmus (CTI) ablation is beneficial in patients with lone atrial flutter (AFL). Background: A high proportion of patients with lone persistent AFL have recurrent episodes of atrial fibrillation (AF) after CTI ablation. However, the benefit of AF ablation in patients with only documentation of AFL has not been determined. Methods: Forty‐eight patients with typical lone persistent AFL (age 56 ± 6; 90% male) were randomized to CTI ablation (Group A; n = 25) or to CTI + PV isolation (PVI) (Group B; n = 23). In addition to PVI, some patients in group B underwent ablation of complex fractionated electrograms and/or creation of left atrial roof and mitral isthmus ablation line in a stepwise approach when AF was induced and sustained for more than 2 minutes. Mean follow‐up was 16 ± 4 months with a 48‐hour ambulatory monitor every 2 months. Results: There were no recurrences of AFL in either group. Six patients in group B (22%) underwent a stepwise ablation protocol. AF organized and terminated in 5 patients during ablation (83%). Complication rate was not significantly different among the groups. Twenty patients in group B (87%) and 11 patients in group A (44%) were free of arrhythmias on no medications at the end of follow‐up (P < 0.05). Conclusions: Ablation of AF at the time of CTI ablation results in a significantly better long‐term freedom from arrhythmias. (J Cardiovasc Electrophysiol, Vol. 22, pp. 34‐38, January 2011)