Cryoballoon Pulmonary Vein Isolation Guided by Transesophageal Echocardiography: Novel Aspects on an Emerging Ablation Technique

Background: Pulmonary vein (PV) isolation using a balloon-mounted cryoablation system is a new technology for the percutaneous treatment of atrial fibrillation (AF). Transesophageal echocardiography (TEE) allows real-time visualization of cryoballoon positioning and successful vein occlusion via color Doppler. We hypothesized that PV mechanical occlusion monitored with TEE could predict effective electrical isolation.
Methods: We studied 124 PVs in 30 patients. Under continuous TEE assessment, a cryoballoon was placed in the antrum of each PV aiming for complete PV occlusion as documented by color Doppler. At the end of the procedure, PV electrical isolation was evaluated using a circumferential mapping catheter.
Results: Of the 124 PVs studied, 123 (99.2%) could be visualized by TEE: the antrum was completely visualized in 80 of them (64.5%), partially in 36 (29.0%), and only disappearance of proximal flow could be observed in the remaining 7 PVs (5.7%). Vein occlusion could be achieved in 111 of the 123 (90.2%) visualized PVs. Postinterventional mapping demonstrated electrical isolation in 109 of 111 occluded PVs (positive predictive value 98.2%) and only in 1 of 12 nonoccluded PVs (negative predictive value 91.7%, P < 0.001). After a mean follow-up of 7.4 ± 3.7 months, 73.3% of patients remained in sinus rhythm without antiarrhythmic drugs.
Conclusion: Color Doppler documented PV occlusion during cryoballoon ablation can predict effective electrical isolation.     

The Permanency of Pulmonary Vein Isolation Using a Balloon Cryoablation Catheter

Chronic PV Isolation With the Cryoballoon . Background: Because of its technical feasibility and presumed safety benefits, balloon cryoablation is being increasingly employed for pulmonary vein (PV) isolation. While acute isolation has been demonstrated in most patients, little data are available on the chronic durability of cryoballoon lesions. Methods and Results: Twelve atrial fibrillation patients underwent PV isolation using either a 23‐mm or 28‐mm cryoballoon. For each vein, after electrical isolation was verified with the use of a circular mapping cathether, 2 bonus balloon ablation lesions were placed. Gaps in balloon occlusion were overcome using either a spot cryocatheter or a “pull‐down” technique. A prespecified second procedure was performed at 8–12 weeks to assess for long‐term PV isolation. Acute PV isolation was achieved in all PVs in the patient cohort (n = 48 PVs), using the cryoballoon alone in 47/48 PVs (98%); a “pull‐down” technique was employed for 5 PVs (1 right superior pulmonary vein, 2 right inferior pulmonary veins, and 2 left inferior pulmonary veins). The gap in the remaining vein was ablated with a spot cryocatheter. During the second mapping procedure, 42 of 48 PVs (88%) remained isolated. One vein had reconnected in 2 patients, while 2 veins had reconnected in another 2 patients. All PVs initially isolated with the “pull‐down” technique remained isolated at the second procedure. Conclusions: Cryoballoon ablation allows for durable PV isolation with the use of a single balloon. With maintained chronic isolation in most PVs, it may represent a significant step toward consistent and lasting ablation procedures. (J Cardiovasc Electrophysiol, Vol. pp. 731‐737, July 2010)     

Balloon technology for catheter ablation of atrial fibrillation

Unlike the initial balloon ablation catheters which were designed to deliver ablation lesions within the pulmonary veins (PVs), the current balloon catheters are fashioned to deliver lesions out of the PV ostia. Using the current generation of balloon ablation catheters, electrical isolation occurs at the level of the PV ostia, but the antral regions are largely unablated because of its initial technical feasibility and presumed safety benefits, balloon cryoablation was being increasingly employed for pulmonary vein (PV) isolation. Other balloon technology—endoscopically navigated laser balloon—was introduced as first real catheter “one fits all” with adjustable size of balloon infation.While high percentage of acute isolation has been demonstrated in most patients with both balloon catheters, little data are available on the chronic durability of cryoballoon or laser balloon lesions. Our own data show that cryoballoon ablation and laser balloon ablation allow for durable PV isolation with the use of a single balloon. With maintained chronic isolation in most PVs, it may represent a significant step toward consistent and lasting ablation procedures.     

Transesophageal Echocardiography during Pulmonary Vein Cryoballoon Ablation for Atrial Fibrillation

We describe our first 20 cases of cryoablation of atrial fibrillation (AF) using transesophageal echocardiography (TEE). Continuous procedural monitoring with TEE by a cardiologist and senior sonographer assists the electrophysiologist in performance of the cryoballoon procedure of AF. Previously using intracardiac echocardiography (ICE) we have found TEE to have better overall procedural imaging, and monitoring for pericardial effusion or thrombus formation. We have found TEE monitoring to be helpful with positioning for interatrial septal (IAS) puncture, catheter tip avoidance of the left atrial appendage (LAA), and guidance of the balloon catheter into each pulmonary vein (PV), with proper positioning within each PV orifice, and documentation of PV occlusion for the cryoballoon procedure. Procedural equipment and the cryoballoon protocol used are presented in detail. The role of TEE imaging during the procedure and in preventing potential dangers is illustrated. It is the goal of this study to demonstrate how the electrophysiology and echocardiography laboratories work together in this cryoablation procedure.     

Pressure monitoring predicts pulmonary vein occlusion in cryoballoon ablation

Purpose

Pulmonary venography is routinely used to confirm pulmonary vein (PV) occlusion during cryoballoon ablation. However, this technique is significantly limited by the risks associated with contrast media, such as renal injury and contrast allergy. We hypothesized that PV occlusion can be predicted by elevation of the balloon catheter tip pressure, avoiding the need for contrast media.

Methods

Forty-eight consecutive patients with paroxysmal atrial fibrillation who underwent PV isolation with the cryoballoon technique were enrolled. The balloon catheter tip pressure was measured in each PV before and after balloon inflation.

Results

We analyzed 200 applications of cryoballoon ablation in 185 PVs (excluding 3 common PVs and 1 extremely small right inferior PV) of 48 patients (age, 70?±?11 years; male, n?=?28; mean left atrial diameter, 38?±?6 mm). Compared with patients with unsuccessful occlusion, patients with successful occlusion demonstrated a larger change in pressure after balloon inflation (6?±?8 vs. 2?±?4 mmHg, P?<?0.001), a lower minimum temperature (??49?±?6 vs. ??40?±?8 °C, P?<?0.001), and a higher PV isolation rate (97 vs. 64%, P?<?0.001). The best cutoff value of a change in pressure for predicting PV occlusion was 4.5 mmHg, with a sensitivity of 67%, specificity of 83%, and predictive accuracy of 72%.

Conclusion

Pressure monitoring is helpful to confirm PV occlusion during cryoballoon ablation.

     

Cryoballoon Pulmonary Vein Isolation Supported by Intracardiac Echocardiography: Integration of a Nonfluoroscopic Imaging Technique in Atrial Fibrillation Ablation

Intracardiac Echo Supported Cryoballoon Ablation . Introduction: Cryoballoon ablation has been adopted for pulmonary vein (PV) isolation (PVI) in many centers. Complete occlusion of PV by an adequately sized balloon is crucial for effectiveness of cryoenergy delivery. The aim of this study was to evaluate intracardiac echocardiography (ICE) as an alternative imaging technique compared to angiographic imaging in cryoballoon PVI. Methods and Results: A total of 75 PVs were treated in 22 patients (61 ± 13 years, 17 male) undergoing PV cryoballoon ablation for drug refractory paroxysmal atrial fibrillation. Decision for an adequate balloon size was based on diameters of the PV antra assessed by ICE and PV angiography. Per PV 2.4 ± 0.4 cryoenergy pulses were applied. Decision for the balloon size was similar either based upon angiography or on ICE. A single 23 or 28 mm balloon was chosen in 10 and 3 patients, respectively. Two different sized balloons were used in 9 patients. PVI was evaluated after 2 cryoenergy applications. Total occlusion of the PV confirmed by ICE color flow Doppler (CFD) during ablation predicted successful PVI in 70 of 75 (93%) and unsuccessful PVI in 8 of 8 (100%). PV flow registered by pulsed wave Doppler at the PV ostium pre‐ and postablation was 0.48 ± 0.10 and 0.51 ± 0.12 m/s, respectively (n.s.). PVI was finally confirmed by entrance block in all PVs. No procedural complications occurred. Conclusions: ICE is a feasible novel imaging technique in cryoballoon ablation procedures. It allows decision for adequate balloon size, exact balloon placement, prediction of acute ablation success, and excludes acute narrowing of PV ostia. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1325‐1330, December 2010)     

A Novel Cryoballoon Technique for Mapping and Isolating Pulmonary Veins: A Feasibility and Efficacy Study

A Novel Cryoballoon Technique . Introduction: The study was designed to evaluate the feasibility and efficacy of a simplified cryoballoon technique in which a microcircular catheter was introduced into the central lumen of a cryoballoon catheter for the purpose of recording pulmonary vein (PV) potentials during ablation procedures and without interchanging catheters. Methods and Results: A total of 23 consecutive patients with paroxysmal atrial fibrillation (AF) were enrolled. A single transseptal puncture was made and a cryoballoon catheter was inserted into the left atrium. A 6‐pole mapping catheter with a 0.035‐inch shaft diameter was introduced into the PV through the central lumen of the cryoballoon catheter. In addition to the function as a recording device, the mapping catheter was also used as a “guide‐wire” during the procedure. A total of 84 PVs (84/92, 91.3%) were completely isolated using this novel cryoballoon technique. In 43 of the 84 veins (51.2%), isolation was observed in real time during the cryoablation; in the remaining 41 veins (48.8%), isolation was confirmed immediately post ablation attempt with the mapping catheter. Procedure time was 152.7 ± 54.9 minutes, and fluoroscopy time was 33.2 ± 17.3 minutes. At follow‐up (7.4 months, range 2–18 months), 17 (73.9%) patients were free from AF. There was 1 occurrence of phrenic nerve palsy during ablation of a right superior PV, which fully resolved after 1 month. Conclusion: The use of a cryoballoon catheter equipped with a 6‐pole micromapping catheter inserted through its central lumen for the purpose of mapping and ablation during PV isolation procedures is both feasible and effective. (J Cardiovasc Electrophysiol, Vol. 21, pp. 626‐631, June 2010)     

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

Aims

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.

Methods

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.

Results

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 %).

Conclusion

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.     

Transesophageal echocardiography: A follow-up tool after catheter ablation of atrial fibrillation and interventional therapy of pulmonary vein stenosis and occlusion

Background Pulmonary vein stenosis (PVS) has been described as a complication after primary catheter ablation of atrial fibrillation (Afib). The purpose of this study was to evaluate the utility of transesophageal echocardiography (TEE) as follow-up tool after catheter ablation of Afib and interventional therapy of PVS and pulmonary vein occlusion (PVO). Methods We report on 28 patients with stenosis (PVS) of 33 pulmonary veins (PVs) and total PVO of 4 veins complicating ablation of Afib assessed by angiography and/or magnetic resonance imaging (MRI). Subsequently, transseptal PV angiograms were performed, followed by recanalization of three totally occluded PVs and balloon dilatation of seven severe PVS (in four cases combined with PV stenting). PVs were analyzed by multiplane TEE in an intraindividual comparison of preablation/preintervention and follow-up measurements of mean and peak flow velocity, velocity time integrals, and diameters. Results Of a total of 28 patients, 14 had mild PVS (n = 14), 9 had moderate PVS (n = 10), 6 had severe PVS (n = 8), and 4 patients showed totally occluded PVs (n = 4). In multivariate analysis flow velocities and vessel diameters showed significant differences (mild, moderate, and severe PVS and PVO; p = 0.001). Interventional benefits of balloon dilatation (n = 10) and stent implantation (n = 4), as well as in-stent restenosis could be detected (p = 0.014). In all recanalized vessels TEE showed reestablished flow. In occluded PVs no flow was detectable. The TEE vessel diameters correlated with angiography data (r = 0.87) and computed tomography/MRI (r = 0.90). Conclusions TEE can be used as a follow-up tool after interventional therapy in patients after catheter ablation and acquired PVS/PVO. Restenosis/in-stent restenosis can be identified by analyzing the vessel diameters and blood flow characteristics.     

Balloon catheter ablation to treat paroxysmal atrial fibrillation: What is the level of pulmonary venous isolation?

BACKGROUND: Unlike the initial balloon ablation catheters that were designed to deliver ablation lesions within the pulmonary veins (PVs), the current balloon prototypes are fashioned to deliver lesions at the PV ostia. OBJECTIVE: Using electroanatomical mapping, this study evaluates the actual location of ablation lesions generated by cryo-based, laser-based, or ultrasound-based balloon catheters. METHODS: In a total of 14 patients with paroxysmal atrial fibrillation, PV isolation was performed using either a cryoballoon catheter (8 patients), laser catheter (4 patients) or ultrasound balloon catheter (2 patients). Patients underwent preprocedural computed tomographic/magnetic resonance imaging. An intracardiac ultrasound catheter was used to aid in positioning the balloon catheter at the PV ostium/antrum. In all patients, sinus rhythm bipolar voltage amplitude maps (using either CARTO with computed tomographic/magnetic resonance image integration or NavX mapping) were generated at baseline and after electrical PV isolation as confirmed by use of a circular mapping catheter. RESULTS: Electrical isolation was achieved in 100% of the PVs. Electroanatomical mapping revealed that after ablation with any of the 3 balloon catheters, the extent of isolation included the tubular portions of each PV to the level of the PV ostia. However, the PV antral portions were left largely unablated with all 3 balloon technologies. CONCLUSION: Using the current generation of balloon ablation catheters, electrical isolation occurs at the level of the PV ostia, but the antral regions are largely unablated.     

应用带有标测功能的冷冻球囊进行肺静脉电隔离

目的 研究应用带有微型环肺静脉标测导管（微环导管）的冷冻球囊完成肺静脉电隔离的可行性.方法 入选2007年12月至2013年3月在德国心脏中心（柏林）接受导管消融的202例阵发性心房颤动（房颤）患者.1次房间隔穿刺后,将冷冻球囊置入左心房.冷冻球囊中央管中放置1根微环导管,作为“导引钢丝”和肺静脉标测导管.结果 电隔离751根肺静脉.其中405根肺静脉（53.9％）在冷冻消融过程中,实时记录到肺静脉电位消失;346根肺静脉（46.1％）在冷冻消融后,回撤微环导管,证实肺静脉电隔离.平均手术时间（131.4±51.7） min,X线曝光时间（23.7±11.3） min.随访33.4（6～63）个月,131例（64.9％）患者无房颤发作.1例患者在隔离右上肺静脉时出现膈神经麻痹,1个月后恢复.结论 使用带有标测功能的冷冻球囊进行肺静脉电隔离是有效、可行的.     

Efficacy and safety of circumferential pulmonary vein isolation using a novel cryothermal balloon ablation system.

OBJECTIVES: We sought to evaluate the efficacy and safety of a novel cryothermal balloon ablation system in creating pulmonary vein (PV) isolation. BACKGROUND: Pulmonary vein isolation using standard radiofrequency ablation techniques is limited by procedure-related complications, such as thrombus formation and PV stenosis. Cryothermal ablation may reduce the risk of such complications. METHODS: Eight dogs underwent circumferential ablation of both superior PVs for either 4 or 8 min using a cryothermal balloon catheter (CryoCath Technologies Inc., Kirkland, Canada). Both fluoroscopy and intracardiac ultrasound (ICE)-guided balloon and Lasso catheter positioning at the PV ostia assessed short-term PV integrity. In six additional dogs, long-term PV integrity was assessed by computed tomography at 16 weeks after ablation. RESULTS: Successful electrical isolation was achieved acutely in 14 of 16 (87.5%) PVs and was confirmed in one-week survival studies in 10 of 12 (83%) PVs. Successful isolation was higher in the absence of any peri-balloon flow leak as seen by ICE (p = 0.015), and with balloon temperatures < or =-80 degrees C (p = 0.015). Cryolesions were located at the veno-atrial junction and were homogeneous, with intact endothelium and free of thrombus formation. Although limited angiographic PV narrowing was noted in the early follow-up period, no significant PV narrowing was seen long-term. Right phrenic nerve injury was seen in 50% of the animals studied at one week. CONCLUSIONS: This novel cryothermal balloon ablation system is effective for isolating PVs, but injury to the right phrenic nerve was noted in this early experience. Further studies are needed to assess the long-term efficacy and safety of this technique.     

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)     

Cryoablation of the pulmonary veins using a novel balloon catheter

Introduction. Pulmonary vein (PV) isolation has emerged as a promising technique for the treatment of patients with drug-refractory atrial fibrillation, however, the achievement of transmural lesions has remained a challenge. We evaluated the ability of a novel balloon-based cryogenic catheter system in achieving transmural lesions for PV isolation. Methods. Six pulmonary vein ostia from three excised ovine hearts and lungs were used in this study. The balloon catheter was deployed and positioned at the ostia of the PVs and a full 8-minute ablation was then performed, while the heart was bathed in a circulating bath of normal saline at 37^∘. Thermocouples positioned on the endocardial (balloon surface—tissue interface) and epicardial surfaces of the ostia were used to determine whether transmural freezing was achieved. Results. The mean temperatures measured on the endocardial and epicardial tissue in six PV ablations were −38.8^∘ ± 6.9^∘C and −10.0^∘ ± 7.5^∘C, respectively. The average pulmonary vein thickness was 3.3 ± 1.4 mm. Conclusions. A novel cryoablation balloon catheter is capable of achieving transmural freezing of the pulmonary vein. The catheter has promise for future clinical therapy of atrial fibrillation.     

Acute procedural efficacy and safety of a novel cryoballoon for the treatment of paroxysmal atrial fibrillation: Results from the POLAR ICE study

Introduction

Pulmonary vein isolation (PVI) is well established as a primary treatment for atrial fibrillation (AF). The POLAR ICE study was designed to collect prospective real world data on the safety and effectiveness of the POLARx^TM cryoballoon for PVI to treat paroxysmal AF.

Methods

POLAR ICE, a prospective, non-randomized, multicenter (international) registry (NCT04250714), enrolled 399 patients across 19 European centers. Procedural characteristics, such as time to isolation, cryoablations per pulmonary vein (PV), balloon nadir temperature, and occlusion grade were recorded. PVI was confirmed with entrance block testing.

Results

Data on 372 de novo PVI procedures (n = 2190 ablations) were collected. Complete PVI was achieved in 96.8% of PVs. Procedure and fluoroscopy times were 68.2 ± 24.6 and 15.6 ± 9.6 min, respectively. Left atrial dwell time was 46.6 ± 18.3 min. Grade 3 or 4 occlusion was achieved in 98.2% of PVs reported and 71.2% of PVs isolation required only a single cryoablation. Of 2190 cryoapplications, 83% had a duration of at least 120 s; nadir temperature of these ablations averaged −56.3 ± 6.5°C. There were 6 phrenic nerve palsy events, 2 of which resolved within 3 months of the procedure.

Conclusion

This real-world usage data on a novel cryoballoon suggests this device is effective, safe, and relatively fast in centers with cryoballoon experience. These data are comparable to prior POLARx reports and in keeping with reported data on other cryoballoons. Future studies should examine the long-term outcomes and the relationship between biophysical parameters and outcomes for this novel cryoballoon.     

Intra- and interatrial conduction abnormalities: hemodynamic and arrhythmic significance

Background

Rigid time-based dosing protocol(s) currently used in the clinic for cryoballoon ablation of atrial fibrillation may be inadequate to guide the circumferential and transmural cryothermal energy transfer across the pulmonary vein (PV) and may result in injury to collateral tissues or electrical gaps between the PV and left atrium (LA).

Objective

A physiologic endpoint (e.g., acute time-to-PV isolation a.k.a. time-to-effect; TTE) may be effective in the determination of a transmural lesion formation and may allow for individualized ablation dosing across each PV.

Methods

Thirty PVs from 15 dogs were randomized into five dosing protocols, including (1) TTE?+?60 s, (2) TTE?+?90 s, (3) TTE?+?120 s, (4) TTE?+?150 s, and (5) 2?×?180 s. Ablations were conducted with a 23-mm second-generation cryoballoon, and TTE was assessed during a freeze by pacing from an inner balloon-lumen circular diagnostic catheter to a quadripolar diagnostic catheter in the coronary sinus. After ablation, animals were survived for 30 to 34 days, and repeat electrophysiology assessment of PV isolation was conducted after which animals were euthanized for gross anatomy and histological examination.

Results

At study termination, efficacy endpoint evaluations were based on maintenance of PV electrical isolation, gross anatomy assessment of PV lesions, and histological examination of PVs. Five efficacy endpoint failures were noted, including the following: 1 PV in the TTE?+?90 sec group; 2 PVs in the TTE?+?120 sec group; 1 PV in the TTE?+?150 s group; and 1 PV in the 2?×?180 s group. Regarding safety, one phrenic nerve injury was observed in the 2?×?180 s cohort. No other complications were observed.

Conclusions

In a canine model, effective PV isolation could be found even in the shortest duration dosing cohort (TTE?+?60 s). One complication (phrenic nerve injury) was observed in the longest duration dosing group (2?×?180 s). Further studies will be required to correlate these results to a 28-mm cryoballoon (more commonly used in the cryoablation of a human LA); however, to date, this is the first reporting of a successful cryoablation using TTE?+?60 s dosing (approximately 90 s total duration of freezing).

     

Anatomic location of pulmonary vein electrical disconnection with balloon-based catheter ablation

Introduction:  Balloon-based catheters are an emerging technology in catheter ablation for atrial fibrillation, which aim to achieve consistent and rapid ablation encirclement of pulmonary veins (PVs). Recent emphasis has been placed on achieving more proximal electrical isolation within the PV–left atrial (LA) junction. We sought to evaluate the precise anatomic level of PV electrical disconnection with current design balloon-based catheters.
Methods and Results:  Thirteen patients with drug-refractory paroxysmal atrial fibrillation undergoing balloon catheter ablation with the endoscopic laser system (CardioFocus) or the high frequency-focused ultrasound system (ProRhythm) underwent electroanatomic mapping (EAM) of the left atrium. Intracardiac echocardiographic (ICE) imaging was used for visualization of the position of the balloon catheter during energy delivery. Detailed point analysis of the location of electrical disconnection was then documented on EAM and with ICE.
Successful electrical isolation was achieved in all 52 PVs. Despite ICE imaging confirming balloon catheter position at the antrum of the PVs, the location of electrical disconnection was demonstrated to be at or near the tubular ostium of the PVs on EAM and on ICE in all patients.
Conclusion:  Current generation balloon-based catheter ablation achieves electrical isolation distal in the LA–PV junction. This may limit the results of such systems in treating nonparoxysmal forms of atrial fibrillation.     

Catheter ablation of atrial fibrillation: Radiofrequency catheter ablation for redo procedures after cryoablation

AIM: To evaluate the effectiveness of two different strategies using radiofrequency catheter ablation for redo procedures after cryoablation of atrial fibrillation.METHODS: Thirty patients(paroxysmal atrial fibrillation: 22 patients,persistent atrial fibrillation: 8 patients) had to undergo a redo procedure after initially successful circumferential pulmonary vein(PV) isolation with the cryoballoon technique(Arctic Front Balloon,CryoCath Technologies/Medtronic).The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy(CARTO;Biosense Webster) depending on the intra-procedural findings.After discharge,patients were scheduled for repeated visits at the arrhythmia clinic.A 7-day Holter monitoring was performed at 3,12 and 24 mo after the ablation procedure.RESULTS: During the redo procedure,a mean number of 2.9 re-conducting pulmonary veins(SD ± 1.0 PVs) were detected(using a circular mapping catheter).In 20 patients,a segmental approach was sufficient to eliminate the residual pulmonary vein conduction because there were only a few recovered pulmonary vein fibres.In the remaining 10 patients,a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction.All recovered pulmonary veins could be isolated successfully again.At 2-year follow-up,73.3% of all patients were free from an arrhythmia recurrence(22/30).There were no major complications.CONCLUSION: In patients with an initial circumferential pulmonary vein isolation using the cryoballoon technique,a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation.     

Cryoballoon ablation for pulmonary vein isolation to treat atrial fibrillation: first experience in Russian Federation

Cryoballon ablation (CBA) for pulmonary vein (PV) isolation is a new method for catheter-based treatment of patients with atrial fibrillation (AF). The purpose of our work is to describe the CBA technique and to report its short-term results. Methods. CBA was performed in 12 patients (8 men; age 53.1+/-5.7 years) with highly symptomatic drug-refractory AF. Paroxysmal AF was present in 11 and persistent AF - in 1 patient. CBA procedure was carried out under general anesthesia with intubation in 6 and under light sedation in 6 patients. After transseptal access and direct PV angiography, 28 mm-cryoballoon was introduced into the left atrium, and more or equal 2 cryoapplications were delivered to each PV, once good PV occlusion was obtained. PV isolation was verified utilizing a circular mapping catheter. Arrhythmia recurrences were monitored every 3 months after ablation using 24-hour Holter, and additional ECG registrations. Holter monitoring was also performed in a case of symptoms. Results. Complete electrical PV isolation was achieved by only cryoballoon ablation in 11 patients, and additional cryocatheter touch-up ablation was required in left PVs in 1 patient. Total procedure time was 203.1+/-34.2 min, fluoroscopy time - 50.5+/-14.0 min. There were no complications. During a mean follow-up period of 136.8+/-59.8 days 9 (75%) patients were free from arrhythmia recurrence after a single procedure. Redo ablation was required in 1 patient, in whom electrical reconnection to all PVs was documented. Conclusion. CBA is a novel promising technique for treatment of patients with AF, and now is available in Russian Federation. The method standardizes and facilitates interventional AF treatment with acute isolation of 96% PVs. The short-term follow-up shows freedom from atrial tachyarrhythmias in 75% of patients.     

在心房颤动持续过程中行肺静脉电学隔离术的可行性

探讨在心房颤动 (简称房颤 )持续过程中行肺静脉电学隔离术的可行性。 9例在导管消融术中房颤持续发作的房颤患者 ,根据肺静脉环状标测电极导管记录的肺静脉激动特征采用 2种方法进行肺静脉开口部的消融 :①肺静脉激动有序且有一种或多种固定的激动顺序 ,采用射频导管消融环状电极记录的最早的激动部位 ;②肺静脉激动无序或无明确的激动顺序 ,首先使用超声球囊导管消融 ,如未达终点再加用射频导管消融。 2种方法的消融终点均为肺静脉电学隔离。总计对 31根肺静脉进行了消融 ,其中 2 8根在房颤心律下消融。房颤心律下电隔离肺静脉的成功率为 92 .9% (2 6根 )。总操作时间和X线透视时间分别为 1 38± 2 1min和 38± 9min。本组无肺静脉狭窄及其他并发症。随访 6 .3± 2 .9(3～ 1 1 )个月后 ,4例 (44.4% )患者无房颤发作 (无需药物 )。结论 :在房颤持续过程中行肺静脉电学隔离术方法可行 ,且较为安全 ;联用超声球囊消融和射频消融对于房颤发作过程中无序或无明确激动顺序的肺静脉具有较好的电学隔离效果。