Pressure‐Guided Cryoballoon Isolation of the Pulmonary Veins for the Treatment of Paroxysmal Atrial Fibrillation

Pressure‐Guided Cryoballoon Pulmonary Vein Isolation. Background: Pulmonary vein (PV) isolation using a balloon‐mounted cryoablation system is a new technology for the percutaneous treatment of atrial fibrillation (AF). Complete PV occlusion during balloon ablation has been shown to predict successful electrical isolation. The aim of this study was to correlate mechanical PV occlusion with changes in a pressure curve recorded at the distal tip of the cryoballoon catheter. Methods and Results: We analyzed 51 PVs in 12 patients (61 ± 6 years old) with paroxysmal AF. At first, PV occlusion via the cryoballoon was documented by changes in the pressure curve. Once the PV is occluded, the pressure curve registered in the vein converts from a left atrial pressure curve to a pulmonary artery pressure curve: the PV wedge curve. Occlusion was then confirmed by transesophageal echocardiography (TEE). Following 2 cryoablation applications, electrical PV isolation was assessed with a circumferential mapping catheter. Under the exclusive guidance of changes in the pressure curve at the tip of the cryoballoon, mechanical occlusion confirmed by TEE was achieved in 47 of 51 PVs (92%). Three PVs required further TEE guidance to achieve occlusion. All 50 occluded veins were electrically isolated after cryoablation. One right inferior vein, which could not be occluded with the balloon, displayed conduction post cryoablation and was isolated by focal ablation. Conclusions: Occlusion and electrical isolation of PVs during cryoballoon ablation can be predicted by the appearance of a PV wedge curve at the tip of the catheter. This new straightforward parameter may facilitate the procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 120‐125, February 2010)     

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.     

Transesophageal Echocardiography for the Diagnosis of Pulmonary Vein Stenosis after Catheter Ablation of Atrial Fibrillation: A Systematic Review

Aims: Pulmonary vein (PV) stenosis is a potentially serious complication of catheter ablation of atrial fibrillation (AF). The optimal method for diagnosis of PV stenosis has not been established. We undertook a systematic review of the literature to investigate the diagnostic performance of transesophageal echocardiography (TEE) for the detection of PV stenosis after catheter ablation of AF. Methods: We searched MEDLINE and EMBASE databases for studies evaluating the diagnostic performance of TEE for the detection of PV stenosis after catheter ablation of AF, compared to a reference standard of PV angiography, magnetic resonance imaging (MRI), or computed tomography (CT). Study quality was assessed using the QUADAS tool. Results: A total of seven studies that included 344 patients (1,344 PVs) met the selection criteria. Of these, three studies used PV angiography as the reference standard, while MRI and CT were used in two studies each. Compared to PV angiography, TEE had sensitivity between 82% and 100% and specificity between 98% and 100%. Compared to MRI, TEE sensitivity was 100% in both studies, while the specificity ranged between 98% and 99%. Compared to CT, TEE had sensitivity between 86% and 100% and specificity of 95%. Quality of the reviewed studies was somewhat limited by the retrospective design in most of the studies. Conclusions: TEE has a high sensitivity and specificity in detecting PV stenosis. Given its wide availability and favorable side effect profile, these data suggest that TEE is very useful tool for the diagnosis of PV stenosis after catheter ablation of AF. (Echocardiography 2010;27:1141‐1146)     

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.     

Life-threatening left atrial wall hematoma secondary to a pulmonary vein laceration: an unusual complication of catheter ablation for atrial fibrillation

Background: Several complications may occur during catheter ablation for atrial fibrillation (AF). We report an unusual case of left atrial wall hematoma without pericardial effusion secondary to a right inferior pulmonary vein (PV) laceration. The use of real-time transesophageal echocardiography (TEE) during the procedure can be useful for early detection of this potentially lethal complication.
Case report: A 49-year-old woman was referred for AF ablation. Her past medical history included severe systemic lupus with chronic renal failure treated with immunosuppressive and steroid drugs. A TEE-guided hybrid approach for AF ablation was performed with circular PV lesions and antrum and ostial electrical isolation. While performing the mitral isthmus line, the TEE showed a growing hematoma at the posterior left atrial wall. Rapidly, left atrium (LA) collapse associated with hemodynamic compromise occurred without any pericardial effusion. The patient was brought to the operating room. No pericardial effusion was seen at the time of surgery. The cardiac exploration showed a right inferior PV laceration. The visual inspection of the LA revealed thin and friable tissue. The patient survived. After 25 months of follow-up, she is still free from symptomatic AF.
Conclusions: Left atrial wall hematoma without pericardial effusion is a rare and life-threatening complication after catheter-based AF ablation. TEE is a valuable monitoring tool to accurately diagnose several acute complications and prompt rapid intervention.     

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)     

Percutaneous Pulmonary Vein Cryoablation to Treat Atrial Fibrillation

BACKGROUND: Cryothermic tissue injury, unlike hyperthermic tissue injury, preserves tissue architecture and causes less thrombus formation, and thus may prevent venous stenosis and stroke in ablating pulmonary veins (PVs) to treat patients with atrial fibrillation (AF). We investigate the feasibility, efficacy, safety and clinical outcome of using percutaneous cryoablation to treat such patients. METHODS: Thirty-one patients who had drug refractory paroxysmal (20) or persistent (11) AF underwent 37 PV ablative procedures using a 4 mm- or 6 mm-tipped 7F cryoablation catheter (CryoCath Technologies Inc., Quebec, Canada). Segmental isolation at the veno-atrial junction was guided by a distal circumferential mapping catheter. RESULTS: A total of 47 PV were ablated, of which 35/47 (74%) were electrically isolated and the remaining 12/47 had attenuation of PV electrograms, altered activation sequence, and marked slowing of left atrial-PV conduction. There was no change in PV diameter, either immediately following cryoablation (21 +/- 5 versus 22 +/- 6, p = 0.69), or at 18 +/- 9 months follow-up (22 +/- 5 versus 22 +/- 5 mm, p = 0.23). There was no clinical thromboembolic event.The duration of cryoablation for each treated PV and procedural duration was 65 +/- 39 and 290 +/- 101 min, respectively. Following cryoablation, 5/30 (6%) were free from AF and 12/30 (43%) showed improvement from previously ineffective antiarrhythmic drug therapy. 13/30 (43%) patients were unchanged by cryoablation. CONCLUSIONS: Cryothermic ablation shows great promise in reducing the risks of PV stenosis and thrombo-embolism associated with PV isolative procedures. However, cryoablation of these veins with linear catheters is time consuming, and the clinical outcomes are disappointing. Alternative catheter designs are required to overcome these difficulties.     

Ablation of focal atrial fibrillation

In the past decades management of atrial fibrillation (AF) has been based mainly on drug therapy. New insights into the pathophysiology of AF initiation and maintenance have provided the background for the design of catheter based procedures. The crucial role of the pulmonary veins (PVs) as triggers of AF paved the way for successful mapping and ablation. Electrical isolation of all PVs using the circular mapping approach has been shown to be an effective procedure, with reported success rates around 70 to 80% in most series. Intracardiac echocardiography is a very helpful adjunctive tool to facilitate correct positioning of the circular catheter at the PV-left atrial junction, as well as to monitor energy delivery and assist transseptal left atrial access. PV stenosis is a potential serious complication, occurring in around 2% of cases. It presents mainly with respiratory symptoms, although it is frequently asymptomatic. Spiral computed tomography is a reliable non-invasive method for imaging the PVs and can be used to screen patients for PV stenosis after radiofrequency ablation. In symptomatic patients, PV dilatation and stenting is the preferred treatment approach.The possibility of curing AF represents a major breakthrough in invasive cardiac electrophysiology. Isolation of all PVs is a very solid endpoint for successful ablation and should be pursued in all patients. It seems to be associated with high success rates over long term follow-up. Future refinements in catheter technology should provide simpler and faster procedures and render catheter ablation of AF more widespread and accepted.     

A Serendipitous Identification of a Lead Extraction Complication

A 57‐year‐old male with a dual chamber pacemaker and symptomatic, persistent atrial fibrillation (AF) accompanying a febrile illness presented for elective transesophageal echocardiography (TEE)‐guided cardioversion. The patient was found to have a large 2.5 cm × 2.3 cm, mobile mass attached to the right atrial lead. Following device and lead extraction, he developed progressive shortness of breath which was attributed to his underlying arrhythmia. One month later, AF ablation was pursued and preablation TEE revealed a dilated main pulmonary artery with a 1.8 cm × 1.6 cm mass in the distal left pulmonary artery, which was corroborated by a 1.4 cm × 2.5 cm filling defect in the descending left pulmonary artery on magnetic resonance angiography (MRA). To our knowledge, this is the first case report to document the distal migration of vegetation material into the pulmonary artery with serial TEE and highlights the risk of pulmonary embolism (PE) in patients with large endocardial lead vegetations undergoing transvenous lead extraction.     

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.     

Pulmonary vein isolation using an occluding cryoballoon for circumferential ablation: feasibility, complications, and short-term outcome.

AIMS: To assess safety, feasibility and short term outcome of pulmonary vein (PV) isolation in paroxysmal atrial fibrillation (AF) with a cryoballoon. METHODS: We consecutively treated 57 patients with a double lumen 23 or 28 mm cryoballoon. The acute results, complications and follow-up over the first three months were analysed, using a comprehensive and intensive follow-up period. RESULTS: During 57 procedures, 185 of 220 targeted PV's were successfully isolated using the cryoballoon (84%) (balloon group, 33 patients). In 33 veins (15%) an additional segmental isolation (hybrid group, 24 patients) was necessary with a standard cryocatheter to achieve isolation. The average procedure times were respectively 211 +/- 108 and 261 +/- 83 minutes (NS), the average fluoroscopy times 52 +/- 36 and 66 +/- 33 minutes (NS). The number of balloon applications did not differ between both groups: respectively a median 9 (4-18) and 10 (5-17) (NS). We observed four phrenic nerve paralysis after ablation of the right superior PV: two resolved immediately after cessation of the cryoenergy, one recovered after 3 months, one persisted up to 6 months. A daily transtelephonic rhythm recording showed a significant drop in mean AF burden from 24% to 10%, 8% and 5% during the three consecutive months of follow-up (p < 0.01 versus baseline). No differences were observed between the treatment groups. 34 patients (60%) were completely free from AF after a single procedure. CONCLUSIONS: Balloon cryoablation of the pulmonary veins with additional segmental isolation if necessary, is a good approach for patients presenting with paroxysmal AF, showing a significant reduction in AF burden after a single procedure. The major complication seems to be phrenic nerve paralysis after ablation of the right superior PV, but this is potentially reversible over several months.     

Pulmonary vein isolation under direct visual identification of the left atrium—pulmonary vein junction using intra-cardiac echography

Introduction: Intra-cardiac echocardiography (ICE) which has some benefits, can be used to obtain detailed anatomy of the heart chambers or large vessels, and the catheter positions, and it has been considered useful for improving the outcome of the ablation. In the present study, we performed pulmonary vein isolation (PVI) under real time monitoring of ICE imaging utilizing an ICE catheter placed at the junction of the left atrium (LA) and PVs (LA-PV junction). Methods: PVI for atrial fibrillation (AF) was performed in 30 cases with drug-resistant AF (mean age: 66-years-old; including 22 males). An ICE catheter utilizing a 9 MHz frequency was inserted into the LA via the atrial septum, and placed at the LA-PV junction. Circumferential ablation was performed in the LA outside of the PV ostium, encircling both the superior and inferior ostia together under ICE imaging. Results: The anatomy of the LA to the PVs and catheter sites were clearly identified by the ICE during the procedure, which enabled a precise and safe catheter manipulation with minimal fluoroscopy. Further, the wall thickness of the PV and LA, and position of the esophagus could be obtained by ICE, facilitating care in adjusting the power and/or duration of the current delivery. Conclusion: ICE imaging of the LA-PV junction permitted real time monitoring of the target sites for PVI during the ablation procedure, and was considered a useful technique for performing PVI.     

Pulmonary vein isolation using transvenous catheter cryoablation for treatment of atrial fibrillation without risk of pulmonary vein stenosis

OBJECTIVES: We sought to evaluate the efficacy and safety of pulmonary vein (PV) isolation using transvenous cryoablation for the treatment of atrial fibrillation (AF). BACKGROUND: Although electrical isolation of PVs with radiofrequency energy for the treatment of AF is feasible, it is associated with a significant risk of PV stenosis. Cryoablation is a new alternative therapy allowing ablation of tissue while preserving its underlying architecture. METHODS: In 52 patients with paroxysmal (n = 45) or persistent (n = 7) AF, PV isolation using the CryoCor cryoablation system (CyroCor Inc., San Diego, California) with a 10F deflectable transvenous catheter was performed as guided by ostial PV potentials. Cryoablation was applied twice at each targeted site (2.5 to 5 min/application). Computed tomography (CT) of the thorax was performed at baseline and at 3 and 12 months to evaluate for PV stenosis. RESULTS: All targeted PVs were completely isolated in 49 (94%) of 52 of patients. Of 152 PVs targeted, 147 (97%) were successfully isolated (mean 3.0 PVs isolated per patient). After a mean period of 12.4 +/- 5.5 months of follow-up, 37 (71%) of 52 patients had no recurrence of AF or were clinically improved, including 29 patients (56%) who had no recurrence of AF with (n = 11) or without the use of anti-arrhythmic drugs. At 3 and 12 months, the CT scan showed no evidence of PV stenosis associated with cryoablation in any patients. CONCLUSIONS: Transvenous catheter cryoablation is an effective method to create PV electrical isolation for the treatment of AF. A clinically satisfactory result can be achieved in 71% of patients with AF, without the risk of PV stenosis.     

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.     

经导管冷冻消融治疗心房颤动的中期疗效评价

目的探讨经导管冷冻消融治疗心房颤动(简称房颤)的安全性和有效性。方法2005年1月至2007年3月本中心共有24例房颤患者接受了经导管冷冻消融肺静脉隔离术,其中22例为阵发性房颤,2例为持续性房颤,消融的终点是肺静脉电位消失。随访成功的定义为术后3个月后无症状性快速性房性心律失常发生。结果22例实现肺静脉电位消失(91.7%),随访15.9±7.5个月,其中18例恢复窦性心律未再发作房颤(8例未服抗心律失常药物),消融首次成功率81.8%(18/22),2例出现心房扑动,1例出现短阵房性心动过速。严重并发症包括1例术后心包压塞,1例一过性窦性停搏伴下壁导联ST段抬高,1例一过性脑气栓,无死亡病例。其中心包压塞者进行了心包穿刺引流术后痊愈。ST段抬高性心室停搏予心室起搏、硝酸甘油静脉点滴后好转。一过性脑气栓的患者经过对症治疗后好转,未留下神经系统后遗症。结论经导管冷冻消融治疗房颤是较安全和有效的。     

Cryoballoon in atrial fibrillation ablation

Encouraging results of ablation therapy in patients with paroxysmal atrial fibrillation (AF) have prompted changes in professional practice guidelines. The most recent European guidelines have suggested that ablation might be offered as first-line therapy in selected patients. Cryoballoon ablation is a promising technology in interventional AF therapy. Two different sizes of the cryoballoon are currently available: a smaller (23?mm) and a larger (28?mm) balloon relative to the ostial diameter of the pulmonary veins. New tools, the circular mapping catheter and the use of intracardiac echocardiography, provide important periprocedural information. A meta-analysis of previous studies revealed outcome data with an AF-free survival rate of 72.83% at the 1-year follow-up in paroxysmal AF patients undergoing cryoballoon ablation. The most frequent, but reversible complication is phrenic nerve palsy with reported incidences up to 10%. All efforts must be taken to overcome this limitation, since the overall major complication rate tends to be lower in cryoballoon compared to radiofrequency ablation. In persistent AF, reported results in cryoballoon ablation had a limited success rate below 50% after a single procedure. A double balloon approach using both cryoballoon sizes might overcome some of the limitations in persistent AF. Prospective data and randomized studies are required. This article outlines the current status of cryoballoon technology in AF ablation therapy.     

Comparison of Cryoballoon and Radiofrequency Ablation of Pulmonary Veins in 40 Patients with Paroxysmal Atrial Fibrillation: A Case‐Control Study

Introduction: Ablation of pulmonary veins (PV) is an established therapeutic option for patients with symptomatic drug‐refractory paroxysmal atrial fibrillation (AF). Radiofrequency (RF) is currently the most widespread energy source for PV ablation. Cryothermal energy applied with a cryoballoon technique as an alternative has recently evolved. Methods and Results: In a case‐control setting, we compared 20 patients with paroxysmal AF who underwent their first PV ablation with the cryoballoon technique to 20 matched patients with conventional RF ablation. In the case of persistent electrical potentials after cryoballoon ablation, it was combined with ablation with a conventional cryocatheter. All patients performed daily event recording for 3 months after ablation procedure. Ablation parameters and success rate after 3 and 6 months were compared. In the cryoballoon group, the overall success rate was 55% (50% in the cryoballoon only group [14 patients] and 66% in the combination group [6 patients]), as opposed to the RF group with 45%. AF episode burden was lower after cryoballoon ablation. There was no significant difference between cryoballoon and RF ablation regarding procedure parameters. In the cryoballoon group, 3 phrenic nerve palsies occurred using the 23 mm balloon that resolved spontaneously. Conclusion: PV ablation with the cryoballoon technique is feasible and seems to have a similar success rate in comparison to RF ablation. Procedure‐ and fluoroscopy duration are not longer than in conventional RF ablation.     

New Technologies for Catheter Ablation of Atrial Fibrillation

The past decade of ablation for atrial fibrillation (AF) has seen the adaptation of catheters designed for “focal” tachycardias or single pathways to perform wide encirclement of the pulmonary veins (PV). During the next decade, technologies designed specifically for PV isolation will emerge. Each system has its unique attributes. The cryoballoon system offers rapid PV isolation and the promise of enhanced safety, whereas the success rate is likely to be similar to catheter-based approaches. Although preclinical studies do suggest a very low likelihood of left atria-esophageal fistula using this technology, concerns of phrenic nerve damage and a small incidence of PV stenosis need to be addressed. It is likely that use of the larger 28-mm balloon will mitigate these concerns. The cryoballoon is also the first balloon technology to be approved by the US Food and Drug Administration for clinical use, and this may gain the technology an early foothold in the AF ablation market. The laser balloon ablation system is a more time-consuming and technically demanding procedure, and the risk of thrombus formation if ablation is performed in stagnant blood is a concern. However, early studies suggest a high rate of persistent PV isolation, which hopefully will translate into high single-procedure efficacy. The Ablation Frontiers system is the only system currently being developed for more persistent forms of AF. This system offers a rapid approach to PV isolation and left atrial defragmentation. The early results do not demonstrate a success rate better than that described for catheter ablation; however, the results are difficult to compare to standard catheter ablation in this recalcitrant patient group without a prospective randomized study.     

A comparison of pulmonary vein ostial anatomy by computerized tomography, echocardiography, and venography in patients with atrial fibrillation having radiofrequency catheter ablation

Accurate assessment of pulmonary vein anatomy is important to procedures that isolate these structures in patients with atrial fibrillation. Various modalities of pulmonary vein (PV) imaging are employed in clinical practice; however, the consistency of findings among the different modalities is unknown. The purpose of this study is to compare PV ostial anatomy by 4 common imaging techniques. Twenty-four patients undergoing catheter-based PV isolation procedures for atrial fibrillation had their PV ostial anatomy determined by cardiac computerized tomography (CT) and transesophageal echocardiography (TEE) before ablation and by intracardiac echocardiography (ICE) and venography during the ablation procedure. The number and maximal dimension of the PV ostia were determined by each imaging modality. In the 24 patients, 98 PV ostia were visualized by CT, 93 by ICE, 81 by TEE, and 71 by venography. The average ostial diameters were similar between CT (1.45 +/- 0.29 cm) and ICE (1.51 +/- 0.22 cm, p = 0.066). Compared with CT or ICE, the ostial diameters were larger with venography (1.67 +/- 0.32 cm) and smaller with TEE (1.16 +/- 0.28 cm, all p <0.001). PV ostial diameters as determined by ICE were significantly correlated with CT measurements (r = 0.57, p <0.001) and venography (r = 0.52, p <0.001). Venography measures of PV diameter were correlated with measures by CT (r = 0.33, p = 0.03). TEE measures were not correlated with any other modality (all p >/=0.43). CT identifies the greatest number of PV ostia followed by ICE. Venography overestimates and TEE underestimates ostial diameters compared with CT or ICE. The PV ostial dimensions obtained by ICE, CT, and venography are all significantly correlated.     

Immediate and medium-term outcomes of cryoballoon-based pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation: single-centre experience

Background

Pulmonary vein (PV) isolation with cryoballoon is a recently developed technique for the treatment of atrial fibrillation (AF) with acceptable mid-term results in terms of the success and safety. The purpose of our study is to identify the periprocedural complications, mid-term success rates and predictors of recurrence after AF ablation with cryoballoon.

Method

A total of 236 patients (54 % male, mean age 54.6?±?10.45 years and 79.6 % paroxysmal AF) with symptomatic AF underwent PV isolation with cryoballoon due to failure with ≥1 antiarrhythmic drug previously. Procedural success, complications and follow-up data were defined according to recent guidelines.

Results

Acute procedural success rate was 99.5 %. Mean procedural and fluoroscopy times were 72.5?±?5.3 and 14?±?3.5 min. At a median of 18 (6–27)?months follow-up, 80.8 % of paroxysmal AF patients and 50.0 % of persistent AF patients were free from AF recurrence. In multivariate regression analysis, body mass index (BMI) (hazard ratio (HR), 1.35; 95 % confidence interval (CI), 1.18–2.93, p?=?0.001), smoking (HR, 2.12; 95 % CI, 1.36–6.67, p?<?0.001), non-paroxysmal AF (HR, 1.26; 95 % CI, 1.12–2.56, p?=?0.024), duration of AF (HR, 1.42; 95 % CI, 1.18–2.61, p?=?0.015), left atrium (LA) diameter (HR, 2.42; 95 % CI, 1.64–5.88, p?<?0.001) and early AF recurrence (HR, 4.88; 95 % CI, 2.86–35.6, p?<?0.001) were independent predictors of AF recurrence following cryoablation.

Conclusion

Our results showed that AF ablation with cryoballoon is effective and safe. Non-paroxysmal AF, duration of AF, smoking, BMI, LA diameter and early recurrence were found to be the most powerful predictors and could be helpful to select patients for appropriate therapeutic strategy.