Pulmonary Vein Disconnection Research Articles

Manifold analysis of the P-wave changes induced by pulmonary vein isolation during cryoballoon procedure

Background/Aim:In atrial fibrillation (AF) ablation procedures, it is desirable to know whether a proper disconnection of the pulmonary veins (PVs) was achieved. We hypothesize that information about their isolation could be provided by analyzing changes in P-wave after ablation. Thus, we present a method to detect PV disconnection using P-wave signal analysis. Methods:Conventional P-wave feature extraction was compared to an automatic feature extraction procedure based on creating low-dimensional latent spaces for cardiac signals with the Uniform Manifold Approximation and Projection (UMAP) method. A database of patients (19 controls and 16 AF individuals who underwent a PV ablation procedure) was collected. Standard 12-lead ECG was recorded, and P-waves were segmented and averaged to extract conventional features (duration, amplitude, and area) and their manifold representations provided by UMAP on a 3-dimensional latent space. A virtual patient was used to validate these results further and study the spatial distribution of the extracted characteristics over the whole torso surface. Results:Both methods showed differences between P-wave before and after ablation. Conventional methods were more prone to noise, P-wave delineation errors, and inter-patient variability. P-wave differences were observed in the standard leads recordings. However, higher differences appeared in the torso region over the precordial leads. Recordings near the left scapula also yielded noticeable differences. Conclusions:P-wave analysis based on UMAP parameters detects PV disconnection after ablation in AF patients and is more robust than heuristic parameterization. Moreover, additional leads different from the standard 12-lead ECG should be used to detect PV isolation and possible future reconnections better.

Cryoablation for atrial fibrillation.

Cryoballoon ablation for the treatment of atrial fibrillation has established itself as an effective and efficient modality for achieving pulmonary vein isolation. Over the past 13 years more than 100,000 Cryoballoon ablation procedures have been performed with the first to fourth generation cryoballoons. Over that time there have been significant advances in our understanding regarding the optimal procedural techniques. The purpose of this "topic in review" is to focus on the practical aspects of performing a Cryoballoon ablation procedure, within the context of the contemporary literature. Specifically there is a focus on how contemporary studies can inform clinical decision making and ensure operators are able to perform a safe and effective procedure.

Simplified synchronous disconnection of pulmonary arteries and veins for right upper lobectomy.

Video-assisted thoracoscopic lobectomy with lymphadenectomy is considered one of the most effective treatments for early non-small cell lung cancer. We developed a novel approach for lobectomy in patients with right upper lung cancer through simplified synchronous disconnection of pulmonary arteries and veins. This study aimed to evaluate the feasibility, efficacy, safety, and cost-effectiveness of this minimally invasive technique in managing right upper lobectomy. From March 2016 to September 2017, 62 patients with right upper lung cancer underwent lobectomy via simplified synchronous disconnection of pulmonary arteriovenous by video-assisted thoracoscopic surgery. All patients were followed up for 6-12 months after the procedure through clinic visits or telephone/e-mail interviews. Of the 62 patients (mean age, 57.2 ± 8.7years), 28 were men (45.2%) and 34 (54.8%) were women. All procedures were successfully performed by thoracoscopy, with a mean operating time of 66.2 ± 9.0min. The mean blood loss was 40.3 ± 19.5mL. Only 1 (1.61%) patient required blood transfusion. The mean number of endoscopic linear stapling devices used was 2.6 ± 0.7. The mean number of lymph nodes harvested was 16.0 ± 1.6. Postoperative pneumonia was encountered in 4 (6.45%) patients. There was no postoperative mortality. The mean length of hospital stay was 5.3 ± 1.3days. Six-month follow-up revealed an excellent clinical result and degree of satisfaction. Simplified synchronous disconnection of pulmonary arteries and veins is a feasible, economical, safe, and effective therapeutic procedure for right upper lung carcinoma. This novel procedure shows promise as a viable surgical approach for right upper lobectomy.

Pulmonary vein isolation with real‐time pulmonary vein potential recording using second‐generation cryoballoon: Procedural and biophysical predictors of acute pulmonary vein reconnection

The study sought to evaluate the procedural and biophysical factors related to acute pulmonary vein isolation (PVI) guided by real-time pulmonary vein (PV) potential recordings. A total of 180 consecutive patients with drug-resistant atrial fibrillation (AF) undergoing CB2 (second-generation version of cryoballoon) ablation were enrolled. Real-time monitoring of PV potentials was obtained using an inner lumen spiral mapping catheter. Acute isolation was achieved in all PVs without touch-up ablation. Real-time assessment of PV disconnection was possible in 611 of 711 (85.9%) PVs. A total of 617 (86.8%) PVs were isolated during the initial freeze. Longer time cycle integration (TCI) (TTI * freeze cycle, TCI) (254.6±112.8 seconds vs 74.1±59.7 seconds, P<0.001), time to isolation (TTI) (94.3±34.0 seconds vs 46.3±26.2 seconds, P<0.001), higher nadir temperature (-45.5±5.3°C vs -50.4±5.5°C, P<0.001), longer time to -40°C (77.3±22.7 seconds vs 55.7±23.2 seconds, P<0.001), faster interval rewarming time at 0°C (9.4±4.3 seconds vs 12.4±4.9 seconds, P=0.008), and total balloon rewarming time (38.1±11.6 seconds vs 47.7±14.0 seconds, P=0.003) were observed in PVs with acute reconduction. TTI ≤65 seconds predicted absence of acute reconnection with 84.2% sensitivity and 75.7% specificity, whereas TCI ≤119 seconds presented 94.7% sensitivity and 80.2% specificity. At a mean follow-up of 4.7±1.4 months, 82.2% of patients were free of AF. None of those with PV reconnections suffered from AF recurrences. The ablation using CB2 is effective in achieving acute PVI. Real-time assessment of PVI could be achieved during CB application in 86% of PVs. The incidence of spontaneous PV reconnection is very low, observed in just 3% of isolated PVs. TTI ≤65 seconds and TCI ≤119 seconds predicted absence of acute PV reconnection. Although they may identify effective cryoapplications in the acute phase, their performance still needs to be verified in the long term.

First And Second-Generation Cryoballoon Ablation Efficacy Restoring And Maintaining Sinus Rhythm In Patients Electrically Selected And Treated For Long-Standing Persistent Atrial Fibrillation After Acute Complete Electrical Disconnection Of Pulmonary Veins From The Left Atrium Demonstrated.

Introduction Cryoballoon ablation (CB) has proven effective to treatment of patients (pts) with atrial fibrillation (AF). However, the isolated efficacy of CB to treat pts with long-standing persistent atrial fibrillation (LSPAF) is less know. We analyzed the acute results and the long-term follow-up of our pts suffering LSPAF and initially treated with CB. Methods A cohort of 44 pts, 37 male (84%) mean age (60±10 year) suffering LSPAF were treated with first (CB1): 15pts, and second (CB2): 29 pts, generation CB. Eight pts (18.1%) had structural heart disease. Prior to CB, all pts were previously electrically cardioverted (CV) and sinus node and A-V nodal function evaluated at electrophysiological study (EP) once in sinus rhythm (SR) before antiarrhythmic drugs (AAD) load. CB ablation procedure was performed after three months waiting period on AAD following CV/EP drug testing. Result CB procedure was performed in 27 (61.4%) in AF, restoring SR in 8 (18.2%). PV isolation (PVI) was achieved in 95.2%. On follow-up of 30±39 months, 16 pts (40%) had AF recurrence. Second procedure (Redo) was performed in 7 pts. After a single procedure, 24 pts (60%) remain in SR without AAD, after Redo, 29 pts (72.5%), and when AAD added, 31 pts (77.5%) remain in SR. Phrenic nerve palsy (PNP) occurred in 9% of pts (75% with CB2). Conclusion CB technique is safe and useful tool to treat pts with LSPAF with 60% success rate maintaining SR without AAD in a long-term follow-up (30±39 months), up to 72.5% after Redo, and to 77.5% when AAD are added. In the majority of pts maintaining SR (77.5%) CB2 was used in 87% of the cases. Patients without structural heart disease along with those who SR was restored during CB showed the best result.

Sinoatrial node electrical activity modulates pulmonary vein arrhythmogenesis

BackgroundSinoatrial node (SAN) dysfunction increases the occurrences of atrial fibrillation (AF). The pulmonary veins (PVs) play a critical role in the pathophysiology of AF. The purpose of this study was to evaluate whether SAN electrical activity can modulate PV arrhythmogenesis. MethodsConventional microelectrodes and multi-electrode array system were used to simultaneously record the electrical activity and conduction properties of rabbit SAN and PV tissue preparations with and without SAN–PV interruptions before and after perfusion with Anemonia sulcata toxin (ATX)-II (100nM) or isoproterenol (1μM). ResultsATX-II significantly increased PV beating rates, which overdrove SAN electrical activity with the occurrences of PV burst firings in 5 (56%) of 9 tissue preparations, and induced SAN–PV conduction block in 6 (67%) of 9 preparations. After SAN–PV disconnection, ATX-II induced burst firing and early afterdepolarizations in 8 (89%) of 9 PVs. Moreover, the multi-electrode array found that ATX-II reversed the electrical conduction between the SAN and PV with an increase in electrical activity from 1.8±0.6 to 2.9±0.6Hz (P<0.05) in SAN–PV preparations (n=7). In contrast, isoproterenol did not reverse electrical conduction between the SAN and PV with an increase in electrical activity from 1.8±0.2 to 3.0±0.3Hz (P<0.005) in SAN–PV preparations (n=7). ConclusionsSAN electrical activity modulates PV arrhythmogenesis. SAN–PV conduction blocks can increase PV arrhythmogenesis.

Real-time assessment of pulmonary vein disconnection during cryoablation of atrial fibrillation: can it be 'achieved' in almost all cases?

Real-time assessment of pulmonary vein (PV) disconnection is possible using an inner circular mapping catheter during cryoablation of atrial fibrillation (AF). However, it has been recently demonstrated that such continuous monitoring may only be possible in <50% of PVs. We hypothesized that a stepwise mapping approach, including pacing manoeuvres, could optimize monitoring of real-time PV disconnection during ablation. Single-centre, prospective observational study (NCT01843465) including 34 consecutive eligible patients (128 PVs) undergoing a first procedure of cryoballoon ablation of AF using the Artic Front Advance(®) 28 mm catheter and a 20 mm diameter Achieve(®) catheter (AC) in all cases. Monitoring of real-time entrance block was possible, when AC was maintained in the standard position (distal to the tip of the Artic Front Advance(®) catheter) in 47 (36.7%) PVs. In an additional 63 cases (49.2%), such monitoring was possible after moving AC to a more proximal position and using different torqueing movements. Finally, using supplemental systematic pacing manoeuvres to test exit block, real-time assessment of PV disconnection was possible in 15 (11.7%) more PVs. Overall, real-time assessment of PV disconnection was possible in 97.7% of cases, after a mean duration of 48.6 ± 33.0 s. Our results suggest that optimal use of the AC, with a systematic stepwise mapping approach, may dramatically improve the real-time monitoring of PV disconnection during AF cryoablation.

Reply to Colli and Romero-Ferrer

Colli et al., commenting on the electrophysiological efficacy of high-intensity focused ultrasound (HIFU), propose a revision of the acute conduction block theory, as a means to confirm effective pulmonary veins (PVs) isolation [1, 2]. Although this proposal could be original, albeit not supported by evidence, it is in contrast with the general agreement surrounding the end-points for atrial fibrillation (AF) ablation. In the areas of consensus on ablation techniques identified by the task force in the recently published Consensus Statement on AF catheter and surgical ablation [3], complete electrical isolation of all PVs should be the goal in every ablation strategy targeting the PVs and/or the PV antrum. So, if the PVs are targeted, electrical isolation should be the goal, and its achievement requires, at a minimum, the assessment and demonstration of conduction block across the PVs lesion. Likewise for surgical PVs, isolation entrance and/or exit block should be validated. Since such acute validation can overestimate success, the Consensus also suggests an extra period of 20 min following PV isolation, to identify and treat PVs reconduction initially masked by the inflammation process, which gives an apparent acute conduction block. The evidence supporting the correlation between complete electrical isolation and clinical efficacy of ablation is clear-cut, since the major predictor of arrhythmia recurrence after catheter ablations is the absence of PVs isolation, indicating restored PV conduction or ineffective PV disconnection. Such a direct cause– effect relationship between PV isolation and cure supports the central role of durable transmurality of the ablations in AF treatment [4]. Despite the penetration properties of HIFU ablations being extensively studied at histology, the results are reported in the very acute context and the conduction block has normally not been evaluated. Hence, inferences between histological transmurality and electrophysiological block in the long-term remain undocumented. Colli and Romero-Ferrer state that in their surgical experience, the freedom from recurrence after HIFU ablation (unpublished data) improves with time, suggesting a progressive increase of the ablation efficacy. They speculate that these results might be related to a putative alternative modality of delayed cell death caused by HIFU. However, a comprehensive study conducted on eight dogs undergoing PV HIFU ablations suggests that the mechanism of permanent injury is irreversible cell death, through coagulative necrosis due to rapid hyperthermal toxicity occurring within the focused zone [5]. Even if different forms of necrotic cell death can be distinguished, based on their initiating mechanisms, i.e. necrosis, necroptosis and secondary necrosis, the downstream cascade of events that occurs thereafter takes place in an invariant fashion, during the following few hours [6]. In conclusion, to the best of the authors’ knowledge, ablation lesions can only get worse with time. Based on current evidence, there is no described biological mechanism that may explain a delayed myocardial cell death where the triggering event occurs during the ablation and the outcome cannot be detected after 3 weeks, as performed in our study.

Close the gap to get a circle ! The role of visual gaps during circumferential pulmonary vein isolation

This editorial refers to ‘Acute electrical isolation is a necessary but insufficient endpoint for achieving durable PV isolation: the importance of closing the visual gap’ by M.A. Miller et al ., on page 653 Since Michel Haissaguerre in the late 1990 delineated the importance of pulmonary vein (PV) triggers and drivers in the pathogenesis of atrial fibrillation (AF), PV isolation has become the cornerstone of successful interventional treatment of AF.1 Initially, segmental or focal PV disconnection was the main treatment strategy. With the awareness of the role of PV antra in the initiation and maintenance of AF, ablation targets have moved away from isolating PVs inside the atria. Nowadays, circumferential ablation around PVs is the main approach. Different energy sources such as radiofrequency, cryo, and laser have been introduced to produce electrical conduction block between PVs and the atrial tissue by creating precise tissue damage. By placement of a circular ablation line around PVs, these are …

An Apparent Way of Achieving Proof of Pulmonary Vein Disconnection during Cryoballoon Ablation

Pulmonary vein isolation (PVI) has established itself as a standard therapy for paroxysmal atrial fibrillation (AF). Still, the most widely performed procedure of point-by-point distal-tip ablation using a 3-dimensional mapping system and a circular catheter to validate PVI remains a complex, elaborative, and time-consuming procedure. This explains the many efforts being made over the recent years to simplify and shorten PVI procedures without compromising the efficacy or the safety. The cryoballoon (Ablation Frontiers, Medtronic, Inc., Minneapolis, MN, USA) is a recently introduced "single shot ablation tool" to facilitate PVI. Initial studies on efficacy and safety of this device are encouraging in patients with paroxysmal AF. However, several controversies remain, such as the need for an additional circular mapping catheter to validate PVI and the lack of on-line PV recording during freezes. One of the most recent developments in this field is the Achieve circular mapping catheter (Ablation Frontiers, Medtronic, Inc.). We describe an apparent case in which this tool is used in conjunction with the cryoballoon.

Is radiofrequency energy a necessary and safe complement to cryotherapy for successful pulmonary vein isolation?

Abstract Introduction Pulmonary vein (PV) isolation is considered the cornerstone of atrial fibrillation (AF) catheter ablation. PV isolation (PVI) by means of cryotherapy has emerged as a promising technique due to both a low thrombogenicity and reduced risk of PV stenosis. The evaluation (need/efficiency/safety) of hybrid therapy (defined as the use of cryotherapy followed by that of radiofrequency energy in a given patient) is the aim of the present study. Methods Thirty-four consecutive patients (26 men, mean age: 56.7 ± 9.3 years) with symptomatic drug-refractory paroxysmal AF underwent PVI using a balloon-cryotherapy (BCT). A maximum of four cryotherapy applications was applied per PV and disconnection assessed thereafter using a circular LASSO® catheter. When necessary, PV disconnection was then performed using a 4 mm irrigated-tip catheter. All patients underwent CT-scan evaluation before discharge to detect acute PV stenosis. Results PVI could be achieved in all patients. Mean procedure duration was 230 ± 42 min and mean fluoroscopy time was 52 ± 13 min. Hybrid therapy was needed to achieve PVI in 26 of 34 (76%). With cryoablation solely, PVI was achieved in 90 of 136 (66%) targeted veins, efficacy being higher in superior as compared to inferior PVs (87% vs. 46%, p Conclusions Our study suggests that hybrid ablation therapy is necessary in most patients to achieve PV disconnection after a maximum of four blinded applications of balloon-cryotherapy (especially in inferior PVs), with a significant short-term success rate.

Cryoballoon temperature predicts acute pulmonary vein isolation

Cryoballoon pulmonary vein isolation (PVI) currently requires a long cryoballoon application (CBA) time of 240 to 300 seconds, thus repeated ineffective CBA prolongs procedure duration. We hypothesized that cryoballoon temperature (CBT) may be used to discriminate between effective and ineffective CBA during freezing. This study sought to evaluate CBT as a predictor of CBA efficiency. Sixty-six patients with atrial fibrillation underwent PVI using the single big (28 mm) cryoballoon technique. CBT was continuously recorded. After each CBA (300 seconds), a Lasso catheter (Biosense Webster, Inc., Diamond Bar, California) was placed into the target pulmonary vein (PV) to determine whether electrical PV disconnection was present. Only the first CBA at each PV was analyzed to avoid cumulative effects. The CBT was lower during CBA at superior compared with inferior PVs. When individual CBAs were grouped according to successful/failed PVI, CBT was lower for those CBAs that resulted in successful PVI at all time points analyzed. To test the performance of CBT to predict failed CBA, receiver-operator curves were constructed. A minimal CBT of ≥ -42°C/ -39°C (superior/inferior PVs) predicted failed PVI with 73%/92% specificity (area under the curve 0.82/0.81); positive predictive value (PPV) 74%/74%. A minimal CBT of < -51°C was invariably associated with PVI. After 120 seconds of freezing, a CBT of ≥ -36°C/ -33°C (superior/inferior PVs) predicted failed PVI with 97%/95% specificity (area under the curve 0.82/0.76); PPV 82%/80%. Balloon temperature predicts successful target PVI during cryoablation and may serve in the early identification of noneffective balloon applications.

Different Image Integration Modalities to Guide AF Ablation: Impact on Procedural and Fluoroscopy Times

Different image integration modalities are available for atrial fibrillation (AF) ablation, but their impact on procedural and fluoroscopy times has not been evaluated yet. Sixty patients (mean age 52.2 ± 12.0 years, 48.3% men, 75% paroxysmal AF) undergoing pulmonary vein (PV) encircling with PV disconnection for symptomatic drug-refractory AF were randomized to ablation with CARTO electroanatomical mapping (Biosense Webster, Diamond Bar, CA, USA) integrated with: (1) preprocedural magnetic resonance imaging (MRI; Group 1); (2) intracardiac echocardiography (ICE; Group 2); (3) preprocedural MRI and ICE (Group 3). PV disconnection was achieved in all patients. Total procedural time (Group 1: 124.7 ± 47.0; Group 2: 112.5 ± 30.4; Group 3: 108.6 ± 34.7 minutes) and total ablation time were similar between groups (P = ns). MRI integration alone required a higher fluoroscopy time (23.8 ± 6.9 in Group 1 vs 11.0 ± 2.3 and 13.9 ± 4.2 minutes in Groups 2 and 3, respectively; P < 0.005) and a longer time spent in the left atrium (109.0 ± 43.5 in Group 1 vs 78.2 ± 29.7 and 74.8 ± 34.3 minutes in Groups 2 and 3, respectively; P = 0.03) in comparison to ICE integration. Addition of MRI to ICE integration showed a tendency for a higher fluoroscopy time in comparison to ICE integration alone (P = 0.06). At a mean follow-up of 9.1 ± 2.2 months, there were no significant differences in AF recurrences among the groups (P = ns). ICE image integration significantly reduces the fluoroscopy time and the time spent in the left atrium in comparison to MRI integration alone. Addition of MRI to ICE integration does not reduce total procedural time and seems to lead to higher fluoroscopy time in comparison to ICE integration alone.

Isolated pulmonary vein tachycardia during atrial fibrillation

A 67-year-old man with a 5-year history of drug-refractory persistent atrial fibrillation (AF) lasting for 7 months prior to the procedure underwent radiofrequency (RF) catheter ablation. The initial AF cycle length (CL) in the coronary sinus (CS) was 162 ms. Ablation was started with isolation of the left pulmonary veins (PV) by creating a continuous linear lesion around the ipsilateral PVs in a distance of *1 cm proximally to the PV ostia. Electrical isolation was confirmed by a single circumferential mapping catheter (Lasso, Biosense-Webster, Diamond Bar, CA, USA) which was sequentially placed in the superior and inferior left PV. After electrical disconnection of the left PVs, accompanied by a slow dissociated rhythm in both PVs, isolation of the right PVs was attempted using the same technique. Initially, a long continuous circular lesion was deployed surrounding both right PVs. Afterwards, potential electrical sleeve conductions of both right PVs were specifically targeted by repeatedly replacing the Lasso catheter in the superior and inferior right vein. However, complete elimination of all PV potentials could only be achieved in the right inferior PV. In contrast, the right superior PV (RSPV) still demonstrated PV potentials with a CL shorter than CS–CL. Although a total of 18 min of RF has been applied in order to isolate the right PVs, apparently no elimination of PV potentials in the RSPV could be achieved. Since the very short CL of the RSPV (CL = 114 ms, Fig. 1) was suggestive for a driving role of this vein in the AF process, external electrical cardioversion was performed to clarify the earliest PV activation during sinus rhythm and, thereby, to facilitate electrical isolation of this potentially ‘‘culprit vein’’. However, no potentials could be demonstrated in the RSPV after cardioversion (Fig. 2). Furthermore, pacing from within the PV demonstrated RSPV exit block. Thus, this observation retrospectively reveals the presence of a persistent PV tachycardia in the electrically isolated RSPV coexisting with ongoing and independently operating AF in the atria. Since complete isolation was confirmed, AF was reinduced and the ablation procedure was continued using the stepwise ablation approach. This approach comprises PV isolation, bi-atrial defragmentation, defragmentation and/or electrical isolation of the coronary sinus and leftatrial linear ablation. The aim of the mapping and ablation process is to gradually eliminate AF sources as represented by an incremental increase of the overall AFCL resulting in AF termination either directly to sinus rhythm or to atrial tachycardia(s) which are targeted until achievement of sinus rhythm [1, 2].

Pulmonary vein isolation with the pulmonary vein ablation catheter (PVAC): is there a price to pay for a 'simpler', shorter procedure?

This editorial refers to ‘Efficacy of multi-electrode duty-cycled radiofrequency ablation for pulmonary vein disconnection in patients with paroxysmal and persistent atrial fibrillation’ by R.P. Beukema et al ., on page 502. Pulmonary vein (PV) isolation (PVI) is currently the most well-accepted ablation strategy for the treatment of atrial fibrillation (AF) because of the demonstration of a pathophysiological role of PV myocardium and a simple and unambiguous endpoint. The technique as originally described utilizes one circumferential mapping catheter placed within the PVs and another ablation catheter in the left atrium (LA) sequentially targeting earliest activation from the LA into the PVs.1 A third catheter placed in the distal coronary sinus is mainly useful to distinguish far-field LA activation from local PV myocardial activation in the left PVs. Appropriate ablation progressively isolates the PV by disconnecting each LA input one by one. Two variants of PVI are practised: circumferential PV ablation (CPVA) which relies on the anatomical creation of a complete isolation barrier and the segmental technique or its variants which depend upon electrical activation to pinpoint the precise input(s) and perform targeted ablation. Although the CPVA technique started life as a single (ablation) catheter-based technique, both techniques as currently practiced require appropriate and stable positioning of two catheters, one to ablate and the other to map and verify isolation. The circular mapping catheter once introduced within a PV of choice should be stable enough to allow the operator to use both hands to manipulate the ablation catheter tip to desired locations around the PV ostial circumference. For anatomical reasons however, this is frequently difficult with the right inferior PV (RIPV) and successful isolation often seems to require more than two hands (or an obedient and stoic assistant!). Both PVI procedures are time consuming including the time taken for each individual ablation, … *Corresponding author. Tel: +41 22 3727202; fax: +41 22 3727229, Email: dipen.shah{at}hcuge.ch

Efficacy of multi-electrode duty-cycled radiofrequency ablation for pulmonary vein disconnection in patients with paroxysmal and persistent atrial fibrillation

A novel multi-electrode pulmonary vein ablation catheter (PVAC) combining circular mapping and duty-cycled multi-electrode radiofrequency (RF) energy delivery has been developed to map and isolate the pulmonary veins (PVs). The aim of this study was to assess the efficacy of multi-electrode RF ablation using the PVAC device. A total of 102 consecutive patients, age 57.9 +/- 9.6 years, with paroxysmal or persistent drug refractory atrial fibrillation (AF) were referred for ablation. All patients had documented AF episodes with an AF duration of 9.3 +/- 7.5 years (range 1.5-25). The mean total procedure time was 139.30 +/- 37.72 (median 135, range 115-172). The mean fluoroscopy time required for PVAC ablation was 17 +/- 12 min (median 16, range 12-33) and the total fluoroscopy time was 32.1 +/- 11.3 min (median 29, range 25-39). The mean multi-electrode RF ablation time required to achieve complete PV isolation was 31 +/- 6.7 min (range 16-51). In eight patients with persistent AF, additional ablations were performed to defragment septal and posterior part of the left atrium. In five patients additional RF ablations using conventional catheters were necessary. After multi-electrode duty-cycled RF ablation, 62 of 102 (60.8%) patients were in sustained sinus rhythm without anti-arrhythmic drugs. The mean follow-up duration was 12.2 +/- 3.9 months (range 6-15). This novel multi-electrode ablation technique can be used for PV isolation and left atrium ablation with a relatively low medium-term success rate after the first ablation of approximately 61%. Larger studies with longer follow-up are required to evaluate the efficacy and whether multi-electrode RF ablation is associated with a different complication rate compared with standard PV isolation.

Role of Pulmonary Veins Isolation in Persistent Atrial Fibrillation Ablation:

The role of pulmonary veins (PV) isolation in patients with persistent atrial fibrillation (AF) is still debated. The aim of this study was to evaluate the adjunctive role of PV isolation in patients with persistent AF who underwent circumferential PV ablation (anatomical approach). We treated 97 consecutive patients presenting with drug-refractory persistent AF by an anatomical approach (group A, n = 36, mean age = 60 +/- 8 years, 29 males) or an integrated approach (group B, n = 61, mean age 59 +/- 10 years, 48 males). In all patients, radiofrequency (RF) ablation was performed by means of a nonfluoroscopic navigation system, in order to anatomically create circumferential lines around the PV. In group B, the persistence of PV potentials was ascertained with a multipolar circular catheter. If PV potentials persisted, RF energy targeting the electrophysiological breakthroughs was delivered to disconnect the PV. Past a 2-month period of observation, success was defined as absence of any atrial tachyarrhythmia recurrence lasting >30 seconds. Total procedure duration (220 +/- 62 minutes vs 140 +/- 43 minutes, P < 0.001), fluoroscopy time (35 +/- 15 minutes vs 17 +/- 9 minutes, P < 0.001), and RF delivery time (48 +/- 22 minutes vs 27 +/- 9 minutes, P < 0.001) were significantly longer in group B than in group A. One cardiac perforation occurred in group A. After 15 +/- 9.1 months, 21 patients in group A (58%) and 34 patients in group B (56%) were free of atrial tachyarrhythmia recurrence (P = 0.9). In patients with persistent AF, who underwent an anatomical approach, electrophysiological confirmation of PV disconnection significantly increased the fluoroscopy and procedural times, without effect on the long-term outcomes.

Image Integration‐Guided Catheter Ablation of Atrial Fibrillation: A Prospective Randomized Study

Several studies have provided details of left atrial anatomy by means of the image integration techniques, particularly focusing on the atypical patterns of the pulmonary veins. To compare, in a prospective, randomized fashion, the conventional method of pulmonary vein disconnection and the image integration-guided approach. Two hundred and ninety consecutive patients (290 patients, mean age 55 +/- 11 years) with drug-refractory paroxysmal or persistent atrial fibrillation were enrolled in the study and were divided into two treatment groups: group 1 (145 patients) undergoing an imaging integration-guided (CartoMerge TM) ablation; group 2 (145 patients) treated by a conventional radiofrequency catheter ablation procedure. The arrhythmia was refractory to at least two antiarrhythmic drugs (IC, amiodarone). Electrical disconnection of all identified pulmonary veins was obtained in all patients of both groups. Bidirectional block of the cavotricuspid isthmus was achieved in 34 group 1 patients and in 40 group 2 patients. Left mitral isthmus ablation was attempted in 52 group 1 patients and in 56 group 2 patients. At a mean follow-up of 14 +/- 12 months, the atrial fibrillation-free survival rate was significantly higher in group 1 patients compared with group 2 patients (88% vs 69%, P = 0.017). The analysis for the subset of patients with previously ineffective ablation (98 patients: 52 group 1 patients and 46 group 2 patients) showed a significantly lower recurrence rate in group 1 versus group 2 (19% vs 48%, P < 0.01). Our data indicate a superior efficacy of the image-integration guided catheter ablation of atrial fibrillation over the long term.

Radiofrequency ablation of paroxysmal atrial fibrillation by mesh catheter

Pulmonary veins isolation usually requires a multielectrode catheter for mapping in addition to the ablation catheter. We describe our experience with a new multipolar catheter designed for simultaneous mapping and ablation (MESH, Bard). We tested the catheter in 15 patients (mean age 61.1 +/- 7.9; eight men) scheduled for paroxysmal atrial fibrillation ablation. The catheter was positioned in front of the pulmonary vein ostia. A pulmonary vein potential was demonstrated in 63.5% of the veins, which were disconnected with a mean of 1.6 radiofrequency applications with a mean time of 351 +/- 125.8 s (range 180-650) for each vein. Mean procedural time was 93 +/- 17.1 min (range 65-120), and fluoroscopy time was 13.7 +/- 4.0 (range 5-15) min. No complications occurred during and after or procedures. Pulmonary veins disconnection with MESH ablator catheter is feasible with short procedural and X-ray exposure time. Further studies are needed to compare this new device to standard multipolar mapping catheters in order to evaluate its ability to correctly identify pulmonary vein potentials and to compare its safety and efficacy.

Identification of conduction gaps in the ablation line during left atrium circumferential ablation: Facilitation of pulmonary vein disconnection after endpoint modification according to electrogram characteristics

Left atrium circumferential ablation (LACA) is a simple, effective treatment for atrial fibrillation (AF), but many pulmonary veins (PV) are not disconnected because of conduction gaps (CG) in the ablation line. This study defined the electrogram characteristics at the CGs and at the PV- left atrium (LA) connection site and assessed the effect of modifying ablation endpoints at these sites. Forty consecutive patients underwent LACA. Phase I: In 15 patients, electrogram characteristics at the LA-PV connection, CGs at the ablation line, and PV disconnection rate were evaluated during LACA with current ablation endpoints (80% reduction in electrogram amplitude or 0.1 mV). Phase II: 25 patients underwent LACA with modified endpoints according to the results of Phase I. Phase I: Fifty-five PVs were analyzed, 17 during sinus rhythm (SR) and 38 during AF. LA-PV connections were characterized by multicomponent electrograms (ME) without an isoelectric line (0.45 +/- 0.43 mV, 77 +/- 21 ms). After LACA, 55% of PVs were disconnected. In 85% of nondisconnected veins, ME (0.11 +/- 0.02 mV) were recorded at CGs where ablation caused PV disconnection. Phase II: Ninety-five PVs, 52 during AF and 43 during SR underwent LACA with modified ablation endpoints at ME sites: Disappearance of late component and voltage reduction to <0.05 mV. Eighty-five per cent of PV were disconnected (95% in SR and 77 % in AF, P <.01). MEs identify LA-PV connections and CGs. Modification of ablation endpoints at these sites should facilitate PV disconnection during LACA.