Pulmonary Vein Potentials Research Articles

Stand-alone mapping using different transluminal mapping catheters--an accurate and safe way to isolate all pulmonary veins with the cryoballoon?

Cryoballoon isolation of the pulmonary veins (PVI) is an effective and safe method in the treatment of patients with paroxysmal atrial fibrillation (PAF). The circular mapping catheter Achieve® (Medtronic Inc., Minneapolis, USA) can be introduced into the pulmonary vein (PV) through the inner lumen of the balloon catheter, allowing online mapping of the PV electrograms during ablation. We prospectively compared the accuracy of this catheter in both available sizes to a standard circular mapping catheter (SCMC) in order to determine bidirectional PV block. Patients with symptomatic PAF underwent cryoballoon ablation using either the Achieve® 15-mm catheter (group 1, 15 patients) or the Achieve® 20 mm (group 2, 15 patients). PV potentials were recorded using Achieve® before, during, and after ablation, and exit block was obtained by pacing from inside the PV. Accuracy of PV potential detection was controlled by a SCMC before and after ablation. Rate of PV which could be isolated exclusively using the Achieve® as guidewire was 98 % (59/60) in group 1 and 93 % (57/60) in group 2. Online signal recording during ablation was possible in 40 and 60 % of PV (p = 0.037), respectively. Final Achieve® diagnosis was accurate in 55/60 (92 %) of the PVs and 12/15 (80 %) of patients in group 1 and 60/60 (100 %) of PV and 15/15 (100 %) of patients in group 2. Stand-alone mapping using Achieve® 15 mm resulted in a significant lack of diagnostic accuracy. Achieve® 20 mm provided excellent diagnostic accuracy comparable to a SCMC and should be preferentially used.

Discrimination of Thoracic Vein Potentials Facilitated by Atrial Pacing during the Isolation

Although electrical thoracic vein (TV) isolation is an established strategy during atrial fibrillation (AF) ablation, discriminating TV potentials from far-field signals is critical for the achievement. One hundred consecutive drug-refractory symptomatic paroxysmal AF patients who underwent AF catheter ablation were included. All patients underwent circumferential pulmonary vein (PV) isolation during distal coronary sinus (CS) pacing with a cycle length of 600 ms. A superior vena cava (SVC) isolation was added during high right atrial (HRA) pacing with the same cycle length in 79 patients in whom SVC potentials were identified. The interval between the near-field PV potentials and far-field atrial signals significantly prolonged more during distal CS pacing than sinus rhythm (SR) in the left superior (26.0 [18.5-32.8] ms to 36.0 [24.3-55.5] ms, P < 0.01) and left inferior PVs (21.0 [14.0-30.0] ms to 40.0 [23.0-56.0] ms, P < 0.01), but not in the right superior (34.0 [20.0-40.0] ms to 23.0 [18.0-36.0] ms, P = 0.13) and right inferior PVs (22.0 [16.0-28.0] ms to 25.0 [18.0-38.0] ms, P = 0.05). The interval between the SVC potentials and far-field atrial signals significantly prolonged more during HRA pacing than SR (20.0 [0-32.0] ms to 34.0 [24.0-46.0] ms, P < 0.01). Electrical isolation was successfully achieved in all TVs without any complications except for transient right phrenic nerve palsy in two patients. Discrimination of ipsilateral left PVs and SVC potentials is facilitated by pacing from the distal CS and HRA, respectively. Better recognition of TV potentials would help to achieve electrical isolation.

Bipolar electrograms characteristics at the left atrial-pulmonary vein junction: Toward a new algorithm for automated verification of pulmonary vein isolation.

Verification of pulmonary vein isolation (PVI) is challenging because of the coexistence of PV and far-field potentials in bipolar electrograms recorded at the left atrial-pulmonary vein (LA-PV) junction. The purpose of this study was to characterize algorithmically LA-PV potentials before and after PVI and to develop an algorithm to differentiate nonisolated from isolated PVs. In 61 patients, we characterized-by type (morphology) and parameters-1440 electrograms recorded during sinus rhythm before and after PVI. Based on vein-dependent prevalence of a given type before and after PVI (first step) and based on vein- and type-dependent cutoff values in parameters specific for recordings before and after PVI (second step), we developed a 2-step algorithm to differentiate nonisolated from isolated PVs. We prospectively validated this algorithm in another dataset of 20 patients. Characteristics before and after PVI were as follows: low voltage (10% ± 7% vs 36% ± 15%), monophasic (13% ± 4% vs 27% ± 9%), biphasic (18% ± 4% vs 21% ± 9%), triphasic (22% ± 5% vs 11% ± 13%), multiphasic (26% ± 7% vs 3% ± 3%), double potentials (11% ± 5% vs 2% ± 1%), peak-to-peak amplitude (0.97 ± 0.21 mV vs 0.35 ± 0.23 mV), maximal slope (0.179 ± 0.033 mV/ms vs 0.071 ± 0.029 mV/ms), minimal slope (0.030 ± 0.003 mV/ms vs 0.024 ± 0.002 mV/ms), and sharpest peak (1.82° ± 0.26° vs 3.45° ± 0.85°, P < .01 for all except biphasic). Overall sensitivity and specificity of the 2-step algorithm was 100% and 87%, respectively. We algorithmically characterized LA-PV potentials before and after PVI in a large dataset (library of types and parameters). This library enabled us to develop an accurate 2-step algorithm to automatically differentiate nonisolated from isolated PVs. The 2-step algorithm is objective and reliable for assessing PV isolation without the need for pacing maneuvers.

Adenosine testing after second-generation balloon devices (cryothermal and laser) mediated pulmonary vein ablation for atrial fibrillation.

Adenosine administration after pulmonary vein (PV) isolation using radiofrequency and cryoablation can cause acute recovery of conduction to the PVs and predicts atrial fibrillation (AF) recurrence. This study evaluated whether adenosine testing after second-generation balloon devices (cryothermal and laser) could reveal dormant PV reconduction and recurrence rate of AF. Out of total 60 patients, 20 patients underwent PV isolation using laser balloon and for the remaining patients, the cryoballoon was used. Following PVI, waiting period of 30 min was obtained. Thereafter, a bolus 15-21 mg of adenosine was injected followed by rapid saline flush. The subsequent response was assessed for each vein using an in situ lasso catheter. Further ablation (if needed) using laser balloon and cryocatheter respectively was done, until no reconduction occurred after repeat adenosine. Acute PV isolation was achieved in all 80 PVs of 20 patients (100 %) using laser device and in 151 PVs (96.2 %) of 38 patients (95 %) using cryoballoon. However, in seven patients (35 %), 11 PVs (13.7 %) (4 LSPV, 2 LIPV, 4 RSPV, and 1 RIPV) showed dormant PV potentials after adenosine administration in laser group. Cryoballoon group showed dormant reconduction in four patients (10 %), four PVs (5 %) [one LSPV, one LIPV, and two RIPV]. The follow-up of 337 ± 92.4 days for cryoballoon and 267 ± 76.9 days for laser balloon group demonstrated similar success rates (85 %). Adenosine testing after PV isolation using second-generation balloon based energy devices (laser and cryothermal) reveals dormant conduction in initially isolated PVs with similar long-term success rate.

Anatomical Characteristics of Pulmonary Veins for the Prediction of Postoperative Recurrence after Radiofrequency Catheter Ablation of Atrial Fibrillation

BackgroundThe relationship between focal pulmonary vein potential and atrial fibrillation (AF) has been confirmed. Pulmonary vein (PV) isolation and circumferential pulmonary vein ablation have been the most commonly used procedures of radiofrequency ablation. However, few studies have investigated the relationship between anatomical characteristics of PV and AF recurrences after radiofrequency ablation.MethodologyFor 267 AF patients treated by radiofrequency catheter ablation, the anatomic structure characteristics of pulmonary veins were assessed by multi-slice spiral computed tomography while the values of left atrial diameter (LAD) were measured with transesophageal ultrasonic cardiogram. After radiofrequency catheter ablation, postoperative recurrence was evaluated during a 10-month term follow-up.Principal FindingsDuring follow-up, postoperative recurrence occurred in 44 patients. The mean diameters of LAD, left superior PV, right superior PV, all left PV, and all superior PV were significantly larger in patients with postoperative recurrence (Recurrence vs. Non-recurrence group; 43.9 ± 6.4 mm vs. 40.7 ± 5.6 mm; 18.4 ± 2.1 mm vs. 17.1 ± 3.1 mm; 18.2 ± 2.8 mm vs. 17.2 mm ± 3.9 mm; 16.4 ± 1.5 mm vs. 15.6 ± 2.5 mm; 18.3 ± 2.1 mm vs. 17.1 ± 3.0 mm; respectively; all P < 0.05). Multivariable survival analysis showed that the type and the course of AF, LAD, and the diameters of all superior PV were the independent risk factors for the postoperative recurrence after radiofrequency catheter ablation.ConclusionsThe enlargements of all superior PV and LAD, long course of diseases, and persistent AF were the independent risk factors for the postoperative recurrence after radiofrequency catheter ablation.

Patterns of Pulmonary Vein Potential Disappearance During Encircling Ipsilateral Pulmonary Vein Isolation Can Predict Recurrence of Atrial Fibrillation

The relationship between pulmonary vein (PV) potential (PVP) disappearance patterns during encircling ipsilateral pulmonary vein isolation (EIPVI) of atrial fibrillation (AF), and outcome was examined. A total of 352 consecutive AF patients (age, 61±12 years; 269 men, 76.4%; paroxysmal AF, n=239; persistent AF, n=73; and long-standing persistent AF, n=40) who underwent initial AF ablation were studied. After EIPVI with a double Lasso technique, pacing was performed from the PV carina to confirm isolation of the carina. PVP disappearance patterns were classified into 3 types: A, both superior and inferior PVP disappeared simultaneously; B, superior and inferior PVP disappeared separately; and C, additional RF applications were required inside the encircling lesions to eliminate the PVP after creating anatomical encircling lesions. The relationship between these patterns and outcome was examined. Six groups were defined according to the combination of right and left ipsilateral PVP disappearance patterns. The incidence of A-A, A-B, B-B, A-C, B-C, and C-C was 7.1%, 14.2%, 16.2%, 15.3%, 27.3%, and 19.9%, respectively. AF recurrence-free rate at 2 years for these 6 groups was 96%, 81%, 78%, 64%, 64%, and 59%, respectively (P<0.02). The incidence of a carina isolation was 153/154 (99.4%) for type A, 221/259 (85.3%) for type B, and 145/290 (50.0%) for type C. PVP disappearance pattern during EIPVI was significantly associated with the incidence of residual PV carina conduction and AF recurrence.

Radiofrequency ablation of paroxysmal atrial fibrillation with the new irrigated multipolar nMARQ ablation catheter: Verification of intracardiac signals with a second circular mapping catheter

During radiofrequency (RF) ablation of paroxysmal atrial fibrillation, a circular multielectrode recording "lasso" catheter is generally positioned within each pulmonary vein (PV) to determine when pulmonary vein potentials (PVPs) are present and when they have been ablated. The new irrigated multipolar nMARQ circular ablation catheter is positioned within the left atrium to create contiguous circular ablation lines around each PV ostium. To determine whether the recordings obtained from the nMARQ catheter position around the PV ostium accurately reproduce the recordings obtained from a lasso catheter positioned within that vein. In 10 patients undergoing RF ablation of paroxysmal atrial fibrillation, we placed an nMARQ and a lasso catheter around and within each PV, respectively. Recordings obtained from both catheters at baseline and after RF ablation were compared. At baseline, recordings of PVPs in both catheters were concordant in 92% of all PVs. However, after RF delivery, the concordance between the nMARQ and lasso recordings was poor. The discordant result most commonly observed was disappearance of "PVPs" from the nMARQ catheter with persistence of PVPs in the lasso catheter (12 of 39 [30%]). Conversely, the delivery of RF frequently resulted in fragmented electrograms (pseudo-PVPs) on the nMARQ catheter despite evidence of PV isolation by lasso catheter recordings. The use of an nMARQ catheter alone, as currently recommended, may lead to underestimation and overestimation of the number of RF applications required to achieve PV isolation.

Real time assessment of pulmonary vein isolation using the novel Achieve mapping catheter during cryoablation

Purpose: The Achieve inner lumen mapping catheter can be used with the cryoballoon to assess real-time isolation of pulmonary vein (PV) during cryoablation and to act as a supporting guidewire during balloon positioning. We sought to analyze the feasibility of this novel catheter and to assess real-time PV isolation during cryoablation. Methods: Patients undergoing 28-mm cryoballoon PVI using the Achieve catheter were included from two centers. Each application lasted 5 min. Real-time PV recording during freezing and time to PV isolation were analyzed. Lastly, the number of applications needed to achieve PV isolation was investigated. Results: 68 pts (47 male; 61±10 yo) were included. Averaged procedure duration and fluoroscopy times were 118±24 min and 29±10 min. During the first application, PV potentials could be detected during freezing in 95.2%, 75.0%, 81.5% and 31.2% of the left superior (LSPV), left inferior (LIPV), right superior (RSPV) and right inferior (RIPV) PVs, respectively. When PV potentials were detected, they appeared in 5±2, 4±2, 4±2, and 3±2 dipoles in and the first cryoenergy application was successful in 68.7%, 82.8%, 80.0% and 90.6% of the LSPVs, LIPVs, RSPVs, and RIPVs, respectively. PV deconnection occurred at -38.4±8.8°C/54.5±34.8sec, -33.3±10.5/46.9±30.4sec, -34.4±12.1/44.4±30.5sec and –37.4±18.0/52.7±27.1sec for the the LSPVs, LIPVs, RSPVs, and RIPVs, respectively. At the end of the procedure, 100% of the PVs were isolated after 1.2±0.6 applications (from 1 to 4). Conclusion: Cryoablation in conjunction with the novel Achieve catheter is feasible, leading to high acute PV isolation rates. Real-time PV recording during freezing can be performed in most of the left PVs and the RSPVs while recording of RIPV potentials is harder due to stability issues.

Comparison of lesion formation between contact force-guided and non-guided circumferential pulmonary vein isolation

Introduction: Monitoring contact force (CF) during ablation would facilitate the procedure of circumferential pulmonary vein (PV) isolation (CPVI). To evaluate the advantage of real-time CF information, we compared the ablation procedure parameters between CF-guided and non-guided CPVI. Methods: The consecutive 31 patients (24 men; mean age, 60 years; 7 with persistent AF) were randomly assigned to CF-guided (CF group, n=17) and CF-non-guided ablation groups (non-CF, n=14). After image integration of CartoSound image of the left atrium (LA) into computed tomography LA image, CPVI was performed using a Thermcool Smarttouch catheter in both groups. In CF group, the operator attempted to keep CF between 10 and 20 g at each ablation site, while in non-CF group, CF information was blinded to the operator. The endpoint of CPVI was the elimination of all PV potentials recorded by circular catheter placed at the PV ostium and PV-to-LA block during pacing from 10 pairs of circular catheter done during sinus rhythm. CF map along CPVI line was created and was divided into 8 segments in each left and right PVs. CPVI procedure and fluoroscopy times, CF in each segment and the number of additional touch-up ablation to complete CPVI were compared between the 2 groups. Results: CPVI was achieved in all patients without any complications. The procedure time for CPVI in non-CF and CF groups were 80±26 and 57±16 minutes (p < 0.001), respectively, and both median fluoroscopy times 0 second (25 to 75%, 0 to 8 and 0 to 0 sec, respectively, p=0.34.) CFs at the anterior segment of the left PV in non-CF group was 4.9±2.8 g, and was significantly smaller than that in CF group (10.6±4.1 g, p < 0.001) The numbers of touch-up ablation in non-CF and CF groups were 6.6±2.8 and 2.9±1.9, respectively (p < 0.001). Conclusion: CF-guided CPVI is effective in reducing the procedure time and additional touch-up ablation, presumably by forming a larger lesion compared with CF non-guided ablation.

GW24-e2989 Linear ablation of left atrium for treatment atrial fibrillation guided by three dimensional electroanatomical mapping but without lasso catheter

ObjectivesThere were few data about linear ablation of left atrium (LA) without lasso catheter guiding, We report the results of linear ablation of LA guided by three dimensional (3-D) electroanatomical...

Adenosine test during confined pulmonary vein fibrillation: how to identify the dormant conduction?

Identifying earliest pulmonary vein (PV) potential (entrance site) during adenosine-exposed reconnection is required to eliminate dormant conduction after PV isolation. However, …

Late pulmonary vein reconnection: insights into mechanisms of atrial fibrillation recurrence after pulmonary vein isolation

A 51-year-old with paroxysmal atrial fibrillation underwent pulmonary vein isolation (PVI) (P1). Pre-ablation pulmonary vein (PV) potentials (*) were noted in all PVs [Panel A ; left superior pulmonary vein (LSPV) shown]. Post-ablation entrance and exit block (†) was documented in all PVs. (Panel 1 B and C ) Repeat procedure (P2) was …

Pulmonary Vein Potentials: Electrophysiological Findings at Initial and Repeat Ablation Procedures

Introduction: Despite successful isolation of pulmonary veins (PVs) at initial ablation (PVI), recurrent AF and PV reconnection at redo are common. Multiple mechanisms have been tested to predict recurrence. We compared PV characteristics at initial procedures with findings at repeat procedures. Methods: Consecutive patients undergoing PVI at a single centre were enrolled over 18 months. Following PVI, each vein was mapped for pulmonary vein potentials (PVPs) firstly in sinus rhythm to look for dissociation (dPVPs) and then during 12 mg bolus of adenosine for recovery (rPVPs). Patients undergoing repeat procedures had all PVs mapped prior to ablation. Results: 736 PVs in 187 patients were mapped. dPVPs were recorded in 75 PVs in 46 patients, rPVPs were recorded in 54 PVs in 38 patients. Twenty-eight patients required repeat procedure at 10 ± 5 months with 109 PVs remapped. In four patients all PVs remained isolated. In 24 patients 44 PVs had reconduction. Of these, 17 had dPVPs and 21 had rPVPs at initial procedure. Seven patients with dPVP also had rPVPs. Thirteen reconnected PVs had neither dPVPs nor rPVPs at initial procedure. Of the 65 veins without reconnection, four had dPVPs and two had rPVPs at initial procedure. The presence of either dPVPs or rPVPs predicted recurrence (PPV 83%, NPV 81%). Conclusions: Dissociated and adenosine unmasked PVP's are relatively common following initial PVI procedure; reconduction of PVP's at repeat procedures is more likely if either of these is detected at initial procedure.

Lessons from dissociated pulmonary vein potentials: entry block implies exit block

AimsPrior reports using pacing manoeuvres, demonstrated an up to 42% prevalence of residual pulmonary vein to left atrium (PV–LA) exit conduction after apparent LA–PV entry block. We aimed to determine in a two-centre study the prevalence of residual PV–LA exit conduction in the presence of unambiguously proven entry block and without pacing manoeuvres.Methods and resultsOf 378 patients, 132 (35%) exhibited spontaneous pulmonary vein (PV) potentials following circumferential PV isolation guided by three-dimensional mapping and a circular mapping catheter. Pulmonary vein automaticity was regarded as unambiguous proof of LA–PV entry block. We determined the prevalence of spontaneous exit conduction of the spontaneous PV potentials toward the LA. Pulmonary vein automaticity was observed in 171 PVs: 61 right superior PV, 33 right inferior PV, 47 left superior PV, and 30 left inferior PV. Cycle length of the PV automaticity was >1000 ms in all cases. Spontaneous PV–LA exit conduction was observed in one of 171 PVs (0.6%). In a subset of 69 PVs, pacing from within the PV invariably confirmed PVLA exit block.ConclusionUnidirectional block at the LA–PV junction is unusual (0.6%). This observation is supportive of LA–PV entry block as a sufficient electrophysiological endpoint for PV isolation.

Pulmonary Vein Isolation in 2012: Is It Necessary to Perform a Time Consuming Electrophysical Mapping or Should We Focus on Rapid and Safe Therapies? A Retrospective Analysis of Different Ablation Tools

Background: Pulmonary Vein Isolation (PVI) is evolving as an established treatment option in atrial fibrillation (AF). Different fluoroscopy-guided ablation devices exist either on the basis of expandable circumferential and mesh designs with mapping and ablation of pulmonary vein potentials, or of a balloon technology, a “single shot” device with a purely anatomical approach. Systematic comparisons between procedure duration (PD), fluoroscopy time (FT) and clinical outcome in using different ablation tools are lacking in the literature.Methods: In a single center retrospective analysis, 119 PVI procedures were performed between August 2008 and March 2011 in paroxysmal AF (PAF, 59.7%) and persistent AF (persAF, 40.3%) patients with mean age of 59.4±10.3 years and history of AF since 8.1±9.7 months. The PVI procedures were evaluated by comparing PD and FT using I) the High Density Mesh Mapper (HDMM), II) the High Density Mesh Ablator (HDMA), and III) the Arctic Front® Cryoballoon. The primary endpoints were FT and PD, the secondary endpoint was procedural safety and efficacy in short- and longterm follow-up.Results: The procedures performed for 119 patients (63.0 % male) included 42 PVIs with the HDMM (35.3 %), 47 with the HDMA (39.5 %) and 30 with the cryoballoon (25.2 %). Comparing the 30 first procedures in groups of 10 in the HDMM and HDMA group, PD and FT fell in the HDMM group (PD from 257.5 to 220.9 min and FT from 80.5 to 67.3 min, both p < 0.05) as well as in the HDMA group (PD from 182.9 to 147.2 min and FT from 41.02 to 29.1 min, both p < 0.05). In the cryoballoon group, there was a steep learning curve with a steady state after the first 10 procedures (PD and FT decreased significantly from 189.5 to 138.1 min and 36.9 to 27.3 min, p values 0.005 and 0.05 respectively). With respect to recurrence of AF in a 24 months follow up, the HDMM and cryoballoon group showed comparable results with ~72% of patients free of arrhythmias. None of the patients died due to severe complications, or suffered a hemodynamic relevant pericardial effusion and/or stroke. Impairment of the phrenic nerve was observed in three patients.Conclusion: Use of the cryoballoon technology was associated with a steep learning curve and a reduced PD and FT; the long-term outcome was similar compared with the HDMM group. The efficacy and safety of the devices but also PD and FT should be respected as the strongest indicators of the quality of ablation. Further studies with long time follow-ups will show if the time for correct mapping of the PV potentials is a price we should be willing to pay or if we should adopt a “wait-and-see” attitude referring the AF recurrence.

Impact of pulmonary vein isolation on atrial late potentials: association with the recurrence of atrial fibrillation

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

Radiofrequency hot balloon catheter ablation for the treatment of atrial fibrillation: A 3-center study in Japan

BackgroundThe safety and efficacy of radiofrequency hot balloon catheter (Toray-Satake balloon [TSB]) ablation for the treatment of atrial fibrillation (AF) was evaluated in a 3-center pilot study. MethodsThirty patients (24 men; age, 61±8 years) with drug-resistant AF (paroxysmal, n=24; persistent, n=6) were evaluated in this study. The pulmonary veins (PVs) and PV antrum were isolated using the TSB under general anesthesia (n=12) or deep sedation (n=18). ResultsComplete PV isolation was achieved in 110 (92%) of 120 PVs, and decreased PV potentials were observed in the right superior PV in 4 patients (13%), left superior PV in 4 patients (13%), and left inferior PV in 2 patients (7%). The mean total procedure time was 104±27min. The mean total fluoroscopic and total application times were 32±14min and 12±2min, respectively. After a single session, 22 (73%) and 20 (67%) of the 30 patients were free from AF after 6 and 11.4±2.2 months of follow-up, respectively. There were no device-related severe complications such as stroke, esophageal fistula, symptomatic PV stenosis, phrenic nerve palsy, or pyloric spasm. ConclusionTSB catheter ablation might be a promising approach for the treatment of drug-resistant AF.

A novel pulmonary vein potential mimic unique to cryoballoon ablation of atrial fibrillation

Figure 1A demonstrates a tracing during cryoballoon ablation of the right inferior pulmonary vein (RIPV). The 28 mm cryo-balloon catheter is positioned at the RIPV ostium (Figure 1B). A 20 mm Achieve circular mapping catheter (CMC) is positioned distallyin the RIPV to ensure catheter stability and optimize PV ostium–cryoballoon contact. During ablation the PN was continuously sti-mulated from a quadripolar catheter positioned in the superior vena cava (1000 ms; 10 mA; 1 ms) resulting in the recording of asurface diaphragmatic CMAP (PHREN2). A signal associated with, yet distinct from, the pacing artefact was recorded on the CMC(PV 1,2 to 8,1;*). This signal was dissociated from the far-field atrial (a) and ventricular electrograms (b) yet simultaneous to thesurface CMAP. Although PV potentials were recorded proximally at the PV ostium there were no pulmonary vein potential(PVPs) recorded in this very distal position (Figure 1C). While mimicking the appearance of a PVP this signal is the intrathoracic rep-resentation of the diaphragmatic CMAP as elicited by PN pacing. It is important to recognize that the possibility for recording diaphrag-matic potentials with very distal CMC positions exists. Differentiation of diaphragmatic CMAPs from PVPs is important in theavoidance of unnecessary right-sided cryoapplications and PN injury.Conflict of interest: none declared.

POSTER PRESENTATIONS

POSTER PRESENTATIONS

Wolf minimaze operation plus endocardial catheter ablation cured chronic atrial fibrillation (one case report)

Case historyThis is a 61-year-old male patient. He had paroxysmal atrial fibrillation (AF) for about 14 years, refractory to propafanone and amiodarone. AF had persisted for 2 years before Wolf...