Incidence and Electrophysiologic Properties of Dissociated Pulmonary Vein Activity Following Pulmonary Vein Isolation During Catheter Ablation of Atrial Fibrillation

Dissociated PV Activity During AF Ablation. Introduction: Pulmonary veins (PV) play an important role in the arrhythmogenesis of atrial fibrillation (AF). Catheter‐based PV isolation is one of the primary treatments for symptomatic drug refractory AF. Following electrical isolation, isolated rhythms in the PV are encountered. The aim of this study was to assess the frequency of postisolation PV activity and classify the different rhythms observed. Methods and Results: This single center prospective study sought to assess the dissociated activity in the PVs following their isolation during AF ablation. In 100 consecutive patients (60 paroxysmal, 40 persistent) undergoing AF ablation, dissociated PV activity was recorded using a multielectrode mapping catheter following antral PV isolation. The dissociated PV activity was classified as (1) silent, (2) isolated ectopic beats, (3) ectopic rhythm, and (4) PV fibrillation. All the PVs were successfully isolated in all the patients. In 91 of 100 patients, there was dissociated activity in at least 1 isolated ipsilateral PV group. There was no significant difference in spontaneous PV activity between patients with paroxysmal and persistent AF (91.7% vs 90%, P = 1.0). Among the 200 isolated ipsilateral PV groups, 64 of 200 (32%) were silent, 86 of 200 (43%) demonstrated isolated ectopic beats, 41 of 200 (20.5%) had ectopic rhythms and 9 of 200 (4.5%) had PV fibrillation. The average cycle length of the PV ectopic rhythm was 2594 ± 966 ms (range 1193–4750 ms). Conclusions: Following PV isolation, a majority of patients demonstrate dissociated activity in at least 1 PV. This finding was evident in patients with both paroxysmal and persistent AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1338‐1343, December 2010)     

Is Empirical Four Pulmonary Vein Isolation Necessary for Focally Triggered Paroxysmal Atrial Fibrillation? Comparison of Selective Pulmonary Vein Isolation Versus Empirical Four Pulmonary Vein Isolation

Background: We questioned whether the empirical four pulmonary vein (PV) isolation (EmPVI) was necessary in patients with paroxysmal atrial fibrillation (PAF) triggered from clearly and reproducibly defined arrhythmogenic PVs.
Methods: We compared the selective or ipsilateral isolation of the PVs triggering AF (SePVI: n = 42) and EmPVI (n = 35) in 77 patients (males 80.5%, mean age 53.0 ± 13.4 years) with PAF who underwent radiofrequency catheter ablation (RFCA). Arrhythmogenic PVs were identified by the immediate recurrence of AF three consecutive times after cardioverting AF.
Results: (1) The duration of the RF energy deliveries (P < 0.01) and total procedure time (P < 0.01) were shorter for the SePVI than the EmPVI. (2) During a mean follow-up of 38.6 ± 23.1 months, the AF recurrence rate was 38.1% in the SePVI group and 25.7% in the EmPVI group (P = NS). (3) A redo-ablation was performed in 25 patients, and 81.0% of the recurrent arrhythmogenic foci were found at a previously ablated PV or ipsilateral PV. (4) In 15.4% of the SePVI and 20.0% of the EmPVI procedures, AF recurred after 32.5 ± 15.2 months of the redo-ablation. Subsequently, the AF-free rate for each group was 88.1% (37/42) in the SePVI group and 91.4% (32/35) in the EmPVI group (P = NS).
Conclusions: In patients with clearly documented arrhythmogenic PVs, the SePVI of the PV triggering the AF or an ipsilateral PV had a comparable long-term success rate and shorter RF energy delivery and procedure times than the EmPVI.     

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.     

Spontaneous and induced pulmonary vein tachycardia after pulmonary vein isolation.

A case is reported of recurrence of paroxysmal atrial fibrillation after pulmonary vein ablation. A second procedure achieved isolation of three pulmonary veins and showed persistence of pulmonary vein tachycardia in one with implications concerning the electrophysiology of atrial fibrillation.     

Dissociated pulmonary vein arrhythmia: incidence and characteristics

INTRODUCTION: The incidence and characteristics of dissociated arrhythmia confined to the pulmonary vein (PV) following disconnection have not been described in a large number of patients with paroxysmal atrial fibrillation. METHODS AND RESULTS: This was a prospective study of 152 patients (29 female, mean age 51 +/- 11 years) referred for catheter ablation of drug-refractory paroxysmal atrial fibrillation. Following ostial ablation, the rate and regularity of any dissociated venous activity was analyzed with and without isoproterenol infusion (to achieve a heart rate of 120-140 beats/min). Patients then were classified according to their venous dissociated activity. Group 1 consisted of patients in whom the dissociated PV spike had a slow rhythm >1,200 ms. Group 2 consisted of patients with spontaneous repetitive dissociated discharges confined in the vein with a cycle length <400 ms. A total of 384 PVs were ablated in 152 patients. Disappearance of all venous potentials was observed in 88% of the treated veins; at least one dissociated venous potential was observed in the remaining 12%. Group 1 activity was seen more often than group 2 (23 patients, mean cycle length 2,300 +/- 1,100 ms vs 13 patients, mean cycle length 179 +/- 77 ms). Dissociated PV arrhythmia was seen most often in the right superior PV (19%).CONCLUSION: Dissociation as the endpoint of PV disconnection was observed in 12% of PVs. Due to the capricious nature of this activity, the actual incidence is almost certainly higher. The dissociated venous rhythm usually is slow and, less commonly, is rapid and repetitive.     

阵发性心房颤动患者环肺静脉消融术后心率变异性变化及其对消融效果的影响

目的 评价环肺静脉消融（CPVA）对阵发性心房颤动（PAF）患者自主神经功能及其预后的影响。方法 连续入选2011年1月至2011年12月就诊的接受CPVA的PAF患者110例[年龄（59.07±11.54）岁,男67例,女43例],患者均接受CPVA至肺静脉电隔离。分别于消融前及术后第2天行动态心电图检查,观察心率变异性（HRV）时域指标变化及其对消融效果的影响。结果 随访14.46±5.57个月,心房颤动（AF）消融成功率为72.45%（71/98）。完成随访的98例患者中,AF无复发71例,设为消融成功组（男45例、女26例）;复发27例,设为消融复发组（男15例、女12例）。两组消融前HRV相似,消融后HRV显著降低（P＜0.05）;消融成功组HRV均较消融复发组进一步显著降低（P＜0.05）。结论 CPVA使HRV显著降低,产生去自主神经效应,这可能是CPVA治疗PAF的机制之一。增加去神经效应对PAF消融长期成功率有一定影响,明确了AF射频消融与HRV之间的关系。     

P波离散度对房颤消融术后预后的影响

目的探讨P波离散度(Pd)对阵发房颤环肺静脉消融(CPVA)术远期预后的预测价值。方法顺序入选116例阵发性房颤患者行CPVA术至肺静脉电隔离。测量和计算算末次消融术前和术后P波最大值(Pmax),P波最小值(Pmin),P波离散度(Pd)。结果随访45.7±19.2个月,112例患者完成了研究,成功率达78.6%。根据随访结果,分为成功组和复发组。两组消融术前Pmax、Pmin和Pmax相似。成功组术后Pmax和Pd显著降低[Pmax(101.2±10.9)vs(.117.3±13.8)ms,p<0.01;Pd(34.8±6.7)vs.(49.3±10.3)ms,p<0.01],而复发组术后P波各参数均无明显变化。两组相比,成功组术后Pd和Pmax较复发组显著降低[Pmax(116.4±9.9)ms,Pd(49.2±8.8)ms]。COX回归分析显示两组左房内径和LVEF均无明显差异;术后Pd和Pmax是阵发房颤CPVA术后远期复发的独立预测因子。结论 Pmax和Pd反映了心房非均质性活动,术后Pmax和Pd可作为阵发房颤CPVA术后远期复发的预测因素。     

Paroxysmal cycle length shortening in the pulmonary veins during atrial fibrillation correlates with arrhythmogenic triggering foci in sinus rhythm

INTRODUCTION: The focal origin of atrial fibrillation (AF) is identified by recording atrial ectopic beats or the ectopic activity that precedes AF. We hypothesized that arrhythmogenic pulmonary veins (PVs) also could be identified during persistent AF. METHODS AND RESULTS: Patients with persistent AF referred for focal ablation were enrolled prospectively. During AF, bipolar electrograms were recorded from each PV for a minimum of 120 seconds, as well as from the right atrium and coronary sinus. The cycle length of activity in each PV was measured during AF and plotted on a frequency histogram. Following cardioversion to sinus rhythm, arrhythmogenic PVs were identified from reinitiation of AF or from ectopic beats. Ten patients were enrolled and 37 PVs analyzed. During AF, 17 PVs demonstrated bimodal cycle length frequency histograms, with periods of paroxysmal short cycle length recording. Following cardioversion, 14 PVs were identified as arrhythmogenic as defined earlier. Each of these arrhythmogenic PVs showed paroxysmal short cycle length recording during AF. Sensitivity was 87%, specificity 91%, positive predictive value 87%, and negative predictive value 100%. CONCLUSION: The arrhythmogenic PVs responsible for the focal activity that triggers AF also demonstrate paroxysmal short cycle length recording during sustained AF. These results demonstrate that arrhythmogenic PVs still can be identified reliably, even during sustained AF.     

Electrophysiology of pulmonary veins

Pulmonary veins were found to be important foci for the genesis and maintenance of atrial fibrillation. Morphological studies have demonstrated the presence of complex anatomic structures and different types of cardiomyocytes in pulmonary veins. Numerous studies have suggested that the combination of reentrant and nonreentrant mechanisms (automaticity and triggered activity) are the underlying arrhythmogenic mechanisms of atrial fibrillation initiation from the pulmonary veins. Electropharmacological studies further indicated that pulmonary veins contained distinct arrhythmogenic activity. Several experimental models have been used to study the pulmonary vein electrical activity and demonstrate the precipitating factors for enhancing the pulmonary vein arrhythmogenic activity. The aim of this review article is to provide a critical overview of the current understanding of the basic and clinical electrophysiology of pulmonary veins and to underscore the importance of future research in this field.     

Ablation of superior pulmonary veins compared to ablation of all four pulmonary veins:

INTRODUCTION: Isolation of all pulmonary veins (PV) is advocated for treatment of paroxysmal atrial fibrillation (PAF). However, the superior PVs are responsible for most AF triggers, whereas the inferior PVs carry the higher risk for ablation-induced ostial stenosis. The aim of this study was to compare a superior PV isolation approach with isolation of all PVs for treatment of PAF. METHODS AND RESULTS: Fifty-two patients with PAF were randomized to either left superior pulmonary vein (LSPV) isolation followed by additional isolation of the right superior pulmonary vein (RSPV) in case of AF recurrence (group A, n = 27) or isolation of all four PVs followed by a repeat procedure in case of recurrence (group B, n = 25). At 1-year follow-up, 11 patients (41%) in group A and 8 patients (32%) in group B had AF relapse (P = 0.55). No significant differences in AF relapse were detected between groups at 3 and 12 months (log rank = 0.36, P = 0.54) and by Cox proportional hazards model analysis (P = 0.62). Nonsignificant PV stenosis was detected in two patients from group B. Total radiofrequency energy delivery and fluoroscopy and procedure times were lower in group A: 8.9 +/- 1.4 minutes vs 25.6 +/- 3.7 minutes (P < 0.001), 22.2 +/- 6.8 minutes vs 62 +/- 10.3 minutes (P < 0.001), and 131.8 +/- 26.5 minutes vs 222.2 +/- 32.3 minutes (P < 0.001), respectively. CONCLUSION: A staged superior PVs isolation approach confers equal success rates but with reduced radiofrequency energy delivery and fluoroscopy and procedure times compared to isolation of all PVs at the initial ablation attempt.     

Safe and Rapid Isolation of Pulmonary Veins Using a Novel Circular Ablation Catheter and Duty-Cycled RF Generator

Background: Ablation of atrial fibrillation (AF) has been one of the most difficult and time-consuming electrophysiological procedures. Due to the rapidly increasing demand for ablation procedures, technical advances would be helpful to reduce complexity and procedure time in AF ablation. Therefore, we investigated the feasibility of a single-catheter technique for pulmonary vein (PV) isolation utilizing a decapolar catheter combined with a duty-cycled, unipolar–bipolar radiofrequency (RF) generator.
Methods: AF mapping and ablation was performed in 21 consecutive patients (mean age 59 ± 12 years, 9 males) with paroxysmal AF (n = 17) and persistent AF (n = 4). The ablation catheter was forwarded to the LA via single-transseptal puncture. All electrodes were energized in 2 to 5 applications per vein, followed by segmental RF applications, as needed, to achieve electrical isolation. To assess left atrial anatomy for purposes of catheter manipulation, and later evaluate the possibility of asymptomatic PV-stenosis, CT or MR imaging was performed both prior to ablation and at 6-month follow-up.
Results: Isolation could be achieved in 85/86 veins (99%). Procedure time for ablation was 81 ± 13 minutes, and fluoroscopy time was 30 ± 11 minutes. There were no procedural complications. Success rate at 6 months was 86% (18/21). MR or CT imaging excluded asymptomatic PV-stenosis.
Conclusion: Mapping and ablation of PVs can be performed in a safe and efficient manner using a single-catheter technique, with short procedure times and minimal learning curve. Thus, this system may be of high interest not only for high volume but all centers performing AF ablation.     

Single‐Catheter Technique for Pulmonary Vein Antrum Isolation: Is It Sufficient to Identify and Close the Residual Gaps Without a Circular Mapping Catheter?

Objectives: The present study was designed to investigate the feasibility and efficacy of single ablation catheter for complete circumferential pulmonary vein antrum (PVA) isolation.
Background: Complete isolation of pulmonary veins is the mainstay for atrial fibrillation (AF) ablation. This is usually performed under the guidance of a circular catheter.
Methods: One hundred and ten consecutive patients with paroxysmal AF were prospectively randomized into two groups: single-catheter approach (group 1) and double-catheter approach (group 2). After performing initial circumferential lesions, residual gaps were mapped and closed with single ablation catheter in group 1 or guided by a circular mapping catheter in group 2 using an electroanatomic mapping system (CARTO™ XP, Biosense-Webster Inc., Diamond Bar, CA, USA).
Results: Complete bilateral PVA isolation was achieved in 22 of the 110 patients after initial ablation. All residual gaps could be correctly identified by activation mapping using single ablation catheter. The distribution of these residual gaps was asymmetric. In group 1, 25 gaps along the right PVA lesions and 49 gaps along the left PVA lesions were identified. All the residual gaps were closed with single-catheter approach. In group 2, 28 gaps on the right side and 53 gaps on the left side were identified using a circular catheter and closed with further ablations. The procedure data and clinical outcomes between the two groups were comparable.
Conclusions: Single ablation catheter technique is feasible and as effective as circular catheter mapping in localizing the residual gaps for PVA isolation during ablation of paroxysmal AF.     

Left atrial flutter after radiofrequency catheter ablation of focal atrial fibrillation

We report an arrhythmic complication in two patients in whom a procedure directed at isolating one or two pulmonary veins had been performed. The complication was related to pulmonary vein disconnection scars after ablation. Both patients developed new clinical tachycardia (atypical atrial flutter) secondary to a reentrant phenomena in the vicinity of a previously ablated pulmonary vein.