Transvenous catheter cryoablation for treatment of atrial fibrillation: results of a feasibility study

Pulmonary vein (PV) isolation using radiofrequency (RF) ablation can induce PV stenosis. Cryoablation may offer a safer alternative energy source for PV isolation. PV isolation with cryoablation was attempted in 31 patients with paroxysmal atrial fibrillation (AF). Event monitors were used to measure the AF episode burden. Serial spiral CT scans were obtained to monitor PV stenosis pre- and postcryoablation. Cryoablation was immediately successful for PV isolation in 29 of 31 patients (94%), with 5.9 +/- 1.2 months of follow-up. Additional RF ablation was performed for AF recurrences in seven patients. The remaining 22 patients with a single cryoablation procedure demonstrated a time-dependent, long-term reduction in the frequency of AF episodes. At 6 months of follow-up, 18 of 22 of cryo-treated only patients (82%) were free of symptomatic AF episodes, and antiarrhythmic drugs were discontinued in 12 of 22 patients. Serial spiral CT scans demonstrated no change in the cryo-treated PV ostial diameter. PV cryoablation was effective to control paroxysmal AF in most patients. Early recurrences of AF postcryoablation were common, though tended to resolve within 6 months postablation, consistent with a process of reverse atrial remodeling. Cryoablation of the PVs did not cause PV stenosis or other serious adverse events.     

Role of Pulmonary Veins Isolation in Persistent Atrial Fibrillation Ablation:

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

Impact of the Preprocedural Frequency of Paroxysmal Atrial Fibrillation on the Clinical Outcome after Catheter Ablation

Background: Pulmonary vein antral isolation (PVAI) is a recommended treatment for symptomatic drug‐refractory paroxysmal atrial fibrillation (PAF). PAF naturally progresses toward persistent AF with an increase in the frequency and duration of AF. The objective of this study was to evaluate whether the preprocedural AF frequency had an impact on the AF recurrence after PVAI in patients with symptomatic PAF. Methods and Results: A total of 362 consecutive patients (61.0 ± 9.8 years; 274 males) with drug‐refractory PAF who underwent PVAI were included. The preprocedural frequency of PAF was daily, weekly, monthly, and yearly in 145 (40.1%), 112 (30.9%), 90 (24.9%), and 15 (4.1%) patients, respectively. There were no significant differences in any of the preprocedural variables between the four groups, except for the number of ineffective antiarrhythmic drugs (AADs). PVAI was successfully performed in all patients. At 12 months after the initial procedure, 63.5% of the entire group of patients were free of AF recurrences without any AADs, respectively. A Cox regression multivariate analysis of the variables including the AF frequency, age, gender, duration of AF, presence of hypertension or structural heart disease, left atrial size, left ventricular ejection fraction, and body mass index demonstrated that the AF frequency was not an independent predictor of AF recurrence after a single ablation procedure (P = 0.194). Conclusions: This study demonstrated that the preprocedural AF frequency did not predict AF recurrence after PVAI in patients with PAF. From the clinical point of view, an additional AF classification based on the preprocedural AF frequency might not be valuable in patients undergoing PVAI. (PACE 2012; 35:1236–1241)     

A Clinical Study of Patients with and Without Recurrence of Paroxysmal Atrial Fibrillation After Pulmonary Vein Isolation

Patients with paroxysmal atrial fibrillation (PAF) can be treated by pulmonary vein (PV) isolation. However, the recurrence rate after this procedure is relatively high. We sought to evaluate the quality of life (QOL) of patients with PAF recurrence after PV isolation and to analyze factors related to recurrences. Seventy-two drug-refractory PAF patients (59 men, 13 women, mean age 52 ± 10) were included. PV isolation was based on the disappearance of PV potentials recorded from a Lasso catheter after segmental ostium ablation. Automatic foci were observed in 47 patients (65.3%) during the procedure. A mean of 3.1 ± 0.9 PVs was isolated. Patients were followed for a mean of 10.3 ± 5.1 months, during which 27 experienced >1 episode of PAF. QOL was scored from 0 (situation before ablation) to 10 (no episode after ablation) based on a questionnaire completed by 69 patients (95.8%). QOL was judged very good in 26 patients (none with PAF recurrences), better in 30 (15 with PAF recurrences), unchanged in 11 (10 with recurrences), and worse in 2 patients with PAF recurrences. Longer histories of PAF and a lower percentage of patients with automatic foci identified during the procedure were observed in the group with, than in the group without recurrences (P < 0.05). PV isolation improved QOL in patients with PAF, including in patients with recurrences. The length of PAF history and observation of automatic foci may be of importance for recurrences of PAF during long-term follow-up.     

Significance of Late Recurrence of Atrial Fibrillation during Long-Term Follow-Up after Pulmonary Vein Isolation

Background and Study Objective : Patients with paroxysmal or persistent atrial fibrillation (AF) can be treated by pulmonary vein (PV) isolation. Although the recurrence rate after the procedure is relatively high, the long-term outcomes after initially recurrence-free procedures remains unclear. We examined the rates of recurrence of AF after PV isolation.
Methods: Our study included 278 consecutive patients with drug-refractory AF (mean age = 53 ± 11 years, 228 men). PV isolation was based on the disappearance of PV potentials recorded from a circumferential catheter after segmental ostium ablation. Cavo-tricuspid isthmus lines and additional atrial lines were performed in 124 and 28 patients, respectively. Patients were monitored for a mean of 26 ± 11 months (range 12–56). Recurrence was defined as ≥1 episodes of symptomatic or asymptomatic AF >1 month after the procedure.
Results: A total of 120 (34) patients had ≥1 recurrence of AF >1 month after the procedure, of whom 14 (4) had a first recurrence >6 months after the procedure. There was a significantly higher recurrence rate among patients with persistent AF.
Conclusions : A relatively high AF recurrence rate was observed after PV isolation. AF may recur late after the ablation procedure, though the majority of recurrences occurred within 6 months after the first procedure. There were no differences in incidence or time of occurrence of late recurrences between patients with paroxysmal versus persistent AF.     

Catheter ablation for atrial fibrillation: mechanism-based curative treatment

The considerable cumulative morbidity and mortality burden resulting from atrial fibrillation has prompted renewed efforts to seek curative and widely applicable therapies. Currently used drugs are not only frequently ineffective at eliminating fibrillation, but may actually be life threatening. Extensive surgery involving both atria has shown that atrial fibrillation can be eliminated in most, if not all, patients, but at a significant cost. The recent discovery of the pivotal role that myocardial extensions into the pulmonary veins play in the initiation, and probably also the maintenance, of atrial fibrillation, has provided a relatively limited target conducive to catheter-based interventions. In experienced hands, paroxysmal atrial fibrillation can be eliminated in more than 85% of patients by a percutaneous intervention lasting less than 3 h with an attendant nonlethal complication risk of 1 to 2%. Thromboembolic complications and pulmonary vein stenosis are the principal complications that may result from this treatment, but their incidence is decreasing. Success rates in patients with persistent or permanent atrial fibrillation are lower, and it is anticipated that increased understanding of the underlying mechanisms will allow doctors to identify those subsets with the greatest potential for benefit from percutaneous catheter-based interventions. Such progress may allow doctors to extend the benefits of eliminating atrial fibrillation to the widest possible range of patients with this recalcitrant disorder.     

Long-Term Follow-Up After Right Atrial Radiofrequency Catheter Treatment of Paroxysmal Atrial Fibrillation

Catheter ablation of paroxysmal atrial fibrillation using long linear lesions in the right atrium is still under investigation, and its long-term follow-up is unknown. Methods: Thirty-six men and nine women (aged 51 ± 12 years) with symptomatic daily episodes of AF for 6 ± 5 years despite the use of 4.7 ± 1.5 antiarrhythmic drugs were studied between July 1994 and January 1996. Progressively longer ablation lines were performed in 3 groups of 15 consecutive patients each, using a 14-electrode catheter or a single-electrode dragging technique. Success was defined as atrial fibrillation elimination or recurrence for no longer than 6 hours over 3 months of observation. Patients who had fewer than 6 hours of atrial fibrillation per month were considered "improved." Medium- (11 ± 4 months) and long-term (26 ± 5 months) results were assessed clinically from a patient's diary and from Holter recordings. Results: After a follow-up of 11 months, 24 patients had a favorable result of the ablation procedure with or without additional antiarrhythmic drug therapy, representing 53% of the original cohort. After 26 ± 5 months of follow-up, these successful results were reduced to 17 patients (37%). Conclusions: After linear atrial ablation, a significant long-term attrition of arrhythmia-free patients was observed. This may be due to a combination of disease progression, incomplete linear block, and ineffective ablation of arrhythmogenic triggers.     

经导管射频消融治疗阵发性心房颤动临床研究

[目的]探讨经导管射频消融治疗阵发性心房颤动的有效性与安全性.[方法]60例阵发性心房颤动患者药物治疗无效且反复发作,采用节段性消融肺静脉电隔离术、CARTO和EnSite 3000三维空间标测系统指导下肺静脉电隔离术3种不同的方法进行肺静脉电位经导管射频消融隔离治疗,术后随访3～41个月.[结果]60例患者中42例(70.0%)经消融成功,10例(16.7%)有效,8例(13.3%)失败,无严重并发症;CARTO和EnSite 3000三维空间标测系统指导肺静脉电隔离术可明显减少X线曝光时间.[结论]经导管射频消融治疗局灶性心房颤动是可行的,对大部分患者是有效的.     

阵发性心房颤动的环肺静脉电隔离单环消融及双环消融术的比较

目的 比较环肺静脉电隔离单环消融和双环消融治疗阵发性心房颤动(简称房颤)的疗效.方法 将40例抗心律失常药治疗无效或出现严重不良反应的阵发性房颤患者,按随机数字表法分为单环消融组和双环消融组,每组20例.单环消融组距肺静脉口0.5 cm作肺静脉单环电隔离线;双环消融组距肺静脉口0.5 cm和1 cm处,分别作肺静脉单环电隔离线.对2组患者手术时间、X线曝光时间,术后6、12个月治愈情况及肺静脉狭窄并发症的发生进行比较.结果 术前2组年龄,房颤发病时间、发作频率,左房内径等比较差异均无统计学意义(均P＞0.05).2组手术时间、术中X线曝光时间比较差异均无统计学意义(均P＞0.05).术后6个月,双环消融组的一次手术治愈率为90％,高于单环消融组的80％(P＜0.05);术后12个月,双环消融组二次手术治愈率为95％,明显高于单环消融组的二次手术治愈率的90％ (P＜0.05).术后6个月2组均未发生肺静脉狭窄.结论 环肺静脉电隔离双环消融治疗阵发性房颤较单环消融效果好.     

Acute and Chronic Pulmonary Vein Reconnection after Atrial Fibrillation Ablation: A Prospective Characterization of Anatomical Sites

Background: Arrhythmia recurrence after atrial fibrillation (AF) ablation is often associated with pulmonary vein reconnection (PVR). We prospectively examined anatomical sites of both acute and chronic PVR. Methods: One hundred and fifty AF patients underwent PV wide encirclement and sites where immediate electrical isolation (EI) occurred were tagged using electroanatomic mapping/CT integration (Cartomerge?, Biosense Webster, Diamond Bar, CA, USA). After 30 minutes PVs were checked and acute PVR sites marked at reisolation. Chronic PVR sites were marked at the time of repeat procedures. Results: On the left, immediate EI sites were predominantly on the intervenous ridge (IVR) and PV‐left atrial appendage (PV‐LAA) ridge. On the right they were at the roof, IVR, and floor of the PVs. Ninety‐eight of one hundred and fifty patients had PVs checked after >30 minutes. Thirty‐two of ninety‐eight had acute PVR. This was mostly on the IVR and PV‐LAA ridge on the left (88%), and on the roof and IVR on the right (78%). At repeat procedure, 38/39 patients had chronic PVR, predominantly on the IVR (61%) and PV‐LAA ridge (21%) on the left, and on the roof, IVR, and floor of the right PVs (79%). There was minimal acute or chronic PVR posteriorly. Acutely PVR occurred close to the immediate EI site 60% of the time, but only 30% of the time chronically. Conclusion: Acute and chronic PVR sites have a preferential distribution. This may be determined by anatomical and technical factors. Knowledge of immediate EI sites may be beneficial acutely, but with chronic PVR a careful survey is required. These findings may help target ablation, improving safety and success.     

Impact of Image Integration on Catheter Ablation for Atrial Fibrillation Using Three‐Dimensional Electroanatomic Mapping: A Meta‐Analysis

Background: Studies comparing the procedural and clinical outcomes of catheter ablation for atrial fibrillation (AF) guided by CartoMerge and that by Carto have achieved mixed results (Carto, Biosense Webster, Diamond Bar, CA, USA). We collected these studies and conducted a meta‐analysis to determine whether CartoMerge results in better procedural and clinical outcomes. Methods and Results: Three randomized controlled trials and two controlled observational studies were collected for analysis. The clinical and procedural outcomes of interest were AF recurrence after catheter ablation, major complications, procedure durations, and fluoroscopy time. Meta‐analysis was performed using RevMan 5.0.18 software (The Cochrane Collaboration, Copenhagen, Denmark) and pooled estimates of effect were reported as risk ratios with 95% confidence intervals (CI). The overall results of this meta‐analysis indicate that catheter ablation for AF guided by CartoMerge is insignificantly associated with a decreased risk of recurrences (RR = 0.76; 95% CI: 0.55–1.04; P = 0.09) and major complications (RR = 0.73; 95% CI: 0.37–1.45; P = 0.37) compared with that by Carto. Conclusion: The image integration using CartoMerge guiding catheter ablation for AF does not improve the main clinical outcomes significantly compared with that by Carto in centers with experienced operators. (PACE 2012; 35:1242–1247)     

Catheter Ablation for Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia in adults, and its prevalence is on the rise. Catheter ablation of AF, once considered a novel procedure, has become the most commonly performed technique for treating patients with severe symptomatic AF. This article reviews the latest American Heart Association/American College of Cardiology/Heart Rhythm Society guideline on the indications for AF and summarizes techniques available to achieve freedom of recurrent arrhythmia and relief from symptoms. Nurse practitioners need to provide guideline-directed care before, during, and after catheter ablation to improve patients’ quality of life and prevent complications.     

Anatomy-Guided Linear Atrial Lesions for Radiofrequency Catheter Ablation of Atrial Fibrillation

The surgical atrial maze procedure has provided proof that atrial fibrillation can be cured by performing atrial incisions based on anatomical and electrophysiological principles. Preliminary reports of attempts at radio frequency catheter ablation of atrial fibrillation utilizing an anatomy-based "linear incision" method have shown the feasibility of the method. However, postprocedural atrial fibrillation recurrence has been common and in addition new, uniform tachycardias have developed in some patients. Both of these outcomes may be in part due to incomplete or inconsistent lesion deployment. This article details the use of the CARTO system for deploying anatomy guided linear atrial lesions for the purpose of curing atrial fibrillation. The procedure is comprised of three phases, which are discussed in detail: (1) baseline map: (2) lesion deployment and; (3) lesion assessment. Using a single standard ablation electrode, lesions can be deployed safely, and complete lesions can be confirmed. Paradigms for right and left atrial incisions are proposed.     

Cost Analysis of Catheter Ablation for Paroxysmal Atrial Fibrillation

WEERASOORIYA, R., et al. : Cost Analysis of Catheter Ablation for Paroxysmal Atrial Fibrillation . RF ablation for paroxysmal atrial fibrillation (PAF) is a curative treatment, which when successful, eliminates the need to take antiarrhythmic drugs, be anticoagulated, and have recurrent physician visits or hospital admissions. The authors performed a retrospective cost comparison of RF ablation versus drug therapy for PAF. The study population consisted of 118 consecutive patients with symptomatic, drug refractory PAF who underwent   1.52 ± 0.71   RF ablation procedures (range 1–4) for PAF. During a follow-up of 32 ± 15 weeks, 85 (72%) patients remained free of clinical recurrence in absence of antiarrhythmic drugs. The cost of RF ablation was calculated in the year 2001 euros on the basis of resource use. The mean cost of pharmacologic treatment prior to ablation was 1,590 euros/patient per year. The initial cost of RF ablation for PAF was 4,715 euros, then 445 euros/year. After 5 years, the cost of RF ablation was below that of ongoing medical management, and continued to diverge thereafter. RF catheter ablation may be a cost-effective alternative to long-term drug therapy in patients with symptomatic, drug refractory PAF. (PACE 2003; 26[Pt. II]:292–294)     

Contemporary Challenges of Catheter Ablation for Atrial Fibrillation

Purpose

Catheter ablation of atrial fibrillation (AF) is now one of the most frequently performed ablation procedures, but there are currently 2 important challenges: achieving permanent/durable rather than transient pulmonary vein isolation (PVI) and improving the results of ablation for the wider patient population with persistent AF.

Methods

Recent technical advances in the technique of ablation and the results of clinical trials aimed at achieving more permanent and durable PVI are reviewed. We also summarize recent advances in identifying atrial fibrosis and in understanding the pathophysiology of AF relevant to selecting patients for ablation of persistent AF.

Findings

The use of contact force–sensing technology, adenosine testing after ablation, and pace capture–guided ablation all have the potential for achieving more durable ablation. Selection of patients suitable for ablation of persistent AF may be improved by assessing the extent of atrial fibrosis with delayed enhancement imaging with cardiac magnetic resonance or by assessing the pattern of atrial electrical activity with the use of complex atrial electrograms. Advances in treatment are likely to result from the recognition of localized rotors and focal sources as primary sustaining mechanisms for all types of human AF and in the use of noninvasive mapping for their identification. Linear ablation to supplement PVI may improve the results of AF ablation.

Implications

Rapidly unfolding advances in the techniques of AF ablation and the understanding of mechanisms of AF hold promise for improving the durability of PVI and for extending the technique to carefully selected patients with persistent AF.