Prevalence of pulmonary vein disconnection after anatomical ablation for atrial fibrillation: consequences of wide atrial encircling of the pulmonary veins.

AIMS: Anatomical and wide atrial encircling of the pulmonary veins (PVs) has been proposed as a cure of atrial fibrillation (AF). We evaluated the acute achievement of electrical PV isolation using this approach. In addition, the consequences of wide encircling of the PVs with isolation were assessed. METHODS AND RESULTS: Twenty patients with paroxysmal AF were studied. Anatomically guided ablation was performed utilizing the CARTO system to deliver coalescent lesions circumferentially around each PV to produce a voltage reduction to <0.1 mV, with the operator blinded to recordings of circumferential PV mapping. After achieving the anatomical endpoint, the incidence of residual conduction and the amplitude and conduction delay of residual PV potentials were determined. Electrical isolation of the PV was then performed and the residual far-field potentials evaluated. Individual PV ablation was performed in all PVs. Anatomically guided PV ablation was performed for 47.3+/-11 min, after which 44 (55%) PVs were electrically isolated. In the remaining 45%, despite abolition of the local potential at the ablation site, PV potentials [amplitude 0.2 mV (range 0.09-0.75) and delay of 50.3+/-12.6 ms] were identified by circumferential mapping. After electrical isolation (12.2+/-11.7 min ablation), 55 (69%) PVs demonstrated far-field potentials; with a greater incidence (P=0.015) and amplitude (P=0.021) on the left compared with the right PVs. At 13.2+/-8.3 months follow-up, 13 patients (65%) remained arrhythmia-free without anti-arrhythmics. In four patients (20%), spontaneous sustained left atrial macrore-entry required re-mapping and ablation. Macrore-entry was observed to utilize regions around or bordering the previous ablation as its substrate. CONCLUSION: Anatomically guided circumferential PV ablation results in apparently coalescent but electrically incomplete lesions with residual conduction in 45% of PVs. Wide encircling of the PVs was associated with left atrial macrore-entry in 20% of patients.     

Non-inducibility post-pulmonary vein isolation achieving exit block predicts freedom from atrial fibrillation.

AIMS: This study evaluates whether non-inducibility of atrial fibrillation (AF) after achieving bi-directional electrical pulmonary vein (PV) isolation is a useful predictor of freedom from AF recurrence. METHODS AND RESULTS: This study included 102 consecutive patients who underwent PV isolation for symptomatic paroxysmal (59%), persistent (32%), or permanent (9%) AF. Patients were followed for 16+/-10 months. Complete isolation of all four PVs was confirmed by demonstration of bi-directional block, defined by both loss of PV potentials and failure to capture the LA by pacing (at 10 mA) 10-14 bipolar pairs of electrodes on a circumferential catheter positioned at the entrance of the PV. Induction of AF by burst pacing on/off isoproterenol was attempted after PV isolation. Freedom from recurrent symptomatic or asymptomatic AF was present in 70% of patients at 6 months and 62% of patients at 12 months. In multi-variable analysis, non-inducibility post-PV isolation (OR=3.84, P=0.047) and paroxysmal AF (OR=4.80, P=0.012) predicted freedom from AF at 12 months. CONCLUSION: Non-inducibility of AF after bi-directional PV isolation predicts maintenance of sinus rhythm. This finding suggests that routine extensive left atrial ablation may be unnecessary.     

Left atrial and pulmonary vein ostial ablation as a new treatment for curing persistent atrial fibrillation.

BACKGROUND: Segmental pulmonary vein (PV) isolation has been performed to eliminate paroxysmal atrial fibrillation (AF). However, this technique is not effective in most patients with persistent AF. METHODS AND RESULTS: Left atrial catheter ablation (LACA) was performed by encircling the left- and right-sided PV 1-2 cm from the ostia, guided by an electroanatomical mapping system in 16 patients with persistent AF (>1 month). Twelve patients (75%) had a history of unsuccessful transthoracic cardioversion and prophylactic antiarrhythmic drugs. Ablation lines were also created in the mitral isthmus and posterior LA. PV isolation was also performed for each PV if there were residual PV potentials after the LACA. After LACA, 38 PV (59%) were completely isolated, and complete PV isolation was achieved with only a few radiofrequency energy applications (2.7+/-2.0 min) on a narrow area of the PV ostium (24+/-15%) in the remaining PV. The mean procedure time was 200+/-38 min. During the follow-up period (17+/-3 months), 12 patients (75%) had normal sinus rhythm and were free of symptomatic AF with (n = 10) or without antiarrhythmic drugs (n = 2). One patient had a stroke just after the procedure. No other complications including PV narrowing (>50%) occurred. CONCLUSION: This approach was effective in persistent AF, however, concomitant use of antiarrhythmic drugs was often required.     

Effect of left atrial circumferential ablation for atrial fibrillation on left atrial transport function

BACKGROUND: The effects of left atrial (LA) circumferential ablation on LA function in patients with atrial fibrillation (AF) have not been well described. OBJECTIVES: The purpose of this study was to determine the effect of LA circumferential ablation on LA function. METHODS: Gated, multiphase, dynamic contrast-enhanced computed tomographic (CT) scans of the chest with three-dimensional reconstructions of the heart were used to calculate the LA ejection fraction (EF) in 36 patients with paroxysmal (n = 27) or chronic (n = 9) AF (mean age 55 +/- 11 years) and in 10 control subjects with no history of AF. Because CT scans had to be acquired during sinus rhythm, a CT scan was available both before and after (mean 5 +/- 1 months) LA circumferential ablation (LACA) in only 10 patients. A single CT scan was acquired in 8 patients before and in 18 patients after LACA ablation. Radiofrequency catheter ablation was performed using an 8-mm-tip catheter to encircle the pulmonary veins, with additional lines along the mitral isthmus and the roof. RESULTS: In patients with paroxysmal AF, LA EF was lower after than before LACA (21% +/- 8% vs 32 +/- 13%, P = .003). LA EF after LA catheter ablation was similar among patients with paroxysmal AF and those with chronic AF (21% +/- 8% vs 23 +/- 13%, P = .7). However, LA EF after LA catheter ablation was lower in all patients with AF than in control subjects (21% +/- 10% vs 47% +/- 5%, P < .001). CONCLUSION: During medium-term follow-up, restoration of sinus rhythm by LACA results in partial return of LA function in patients with chronic AF. However, in patients with paroxysmal AF, LA catheter ablation results in decreased LA function. Whether the impairment in LA function is severe enough to predispose to LA thrombi despite elimination of AF remains to be determined.     

三维标测系统指导下环肺静脉消融治疗心房颤动

目的 探讨三维标测系统指导下环肺静脉消融治疗心房颤动的安全性和有效性.方法 阵发性心房颤动92例和持续性或永久性心房颤动36例,接受环肺静脉消融术.采用Carto电解剖标测系统,进行环肺静脉左心房线性消融,消融终点为肺静脉电隔离.手术结束时对心律仍为心房颤动者行同步直流电心脏复律.结果 完成"解剖学"环形消融线256条,其中58.6%达到电隔离肺静脉的终点,经寻找缝隙补充消融后最终248条(96.9%)消融线达到终点.手术时间(231±45)min、X线曝光时间(42±13)min和放电时间(66±17)min.术后随访平均10个月,无复发101例(78.9%).接受了再次手术15例,心内电生理检查证实14例有左心房-肺静脉传导,射频消融成功并随访30～270 d,两次射频消融术后总成功率为87.5%,其中阵发性心房颤动成功率为93.0%,持续性或永久性心房颤动为76.7%.并发症发生率为6.2%,包括心包填塞2例、小脑梗死2例、股静脉穿刺部位血肿1例和左侧大量血胸1例,经治疗后均痊愈.结论 以肺静脉电隔离为目标的环肺静脉消融术治疗心房颤动有效和安全.     

Circumferential mapping and electric isolation of pulmonary veins in patients with atrial fibrillation

Information about the clinical efficacy and complications of the circumferential mapping and isolation of the pulmonary veins (PVs) in patients with atrial fibrillation (AF) is still limited. The present study included 75 patients (mean age 58 +/- 11 years, 20 women) with paroxysmal (n = 69) or persistent AF (n = 6). Mapping of PVs was performed with a circumferential mapping catheter. After preferential PV-left atrium (LA) electric inputs were defined, radiofrequency ablation was performed until complete isolation of the PVs from the LA was achieved. A total of 226 PVs were mapped; 195 (86%) showed typical PV potentials. Complete isolation of PVs from the LA was achieved in 173 PVs (89%). Detailed follow-up, including 7-day Holter monitoring at 1, 4, 9, and 12 months after intervention was performed. If AF reoccurred, PVs were mapped and reisolated. After a mean follow-up period of 230 +/- 133 days, 38 of 75 patients (51%) were in sinus rhythm. At 1, 4, and 9 months of follow-up, 31 of 65 patients (48%), 36 of 53 patients (68%, p = 0.04 as compared with the first month), and 21 of 28 patients (75%, p = 0.025 as compared with the first month), respectively, were in sinus rhythm. During follow-up, 30 patients (40%) underwent a second ablation procedure due to recurrence. Recurrences were related to resumption of PV muscle-left atrial conduction (27 patients) and/or extra PV foci (12 patients) or nonablated PVs (8 patients). Complications occurred in 17 patients (22%). PV stenosis was detected in 13 patients (25% to 50% in 7 patients and >50% in 6 patients). Pericardial effusion occurred in 4 patients. It was concluded that isolation of the PV from the LA is moderately effective in the prevention of AF recurrence and could be associated with serious acute and long-term complications.     

Bi-directional electrical pulmonary vein isolation as an endpoint for ablation of paroxysmal atrial fibrillation

Objective Various approaches to pulmonary vein (PV) isolation have shown variable efficacy in patients with paroxysmal atrial fibrillation (AF). The purpose of this study is to report the efficacy and safety of routine isolation of all PVs using an endpoint of bi-directional electrical block. Materials and methods This study included 85 consecutive patients who underwent PV isolation for symptomatic paroxysmal AF. Complete isolation of all PVs was confirmed by demonstration of bi-directional block: (a) loss of all PV potentials, and (b) failure to capture the left atrium by pacing 10–14 bipolar pairs of electrodes on a circumferential catheter placed at the entrance of the PV at 10 mA with 2 ms pulse width. Induction of AF by burst pacing was attempted after PV isolation. Results Freedom from symptomatic or asymptomatic AF (detected by event recorder or Holter monitor) was present in 85% and 76% of patients at 6 and 12 months. Additional mitral isthmus or posterior left atrial lines were performed in seven patients with inducible atrial arrhythmias after PV isolation. Atrial tachycardia occurred in three of these patients during long-term follow-up and in two of the 78 patients without additional ablation. Conclusion The use of bi-directional block circumferentially across all PV ostia as an electrophysiological endpoint may improve results of PV isolation for paroxysmal AF. Avoidance of routine additional left atrial ablation lines may decrease the risk of atrial tachycardia and esophageal fistula. Dr. Essebag is the recipient of a Clinician Scientist Award from the Canadian Institutes of Health Research (CIHR). Dr. Reynolds is the recipient of grant #1K23HL077171-01 from the National Heart, Lung, and Blood Institute (NHLBI).     

Effects of circumferential ostial radiofrequency lesions on pulmonary vein activation recorded with a multipolar basket catheter

AIMS: Two different ablation procedures are performed to cure patients of atrial fibrillation (AF): (1) the electrophysiological pulmonary vein (PV) isolation, and (2) the anatomical circumferential ablation of all four PV ostia. The aim of this study was to determine the effects of circumferential radiofrequency lesions around the ostia on PV activation. METHODS AND RESULTS: In 34 patients with drug refractory paroxysmal (N = 22) or persistent (N = 12) AF a 31-mm basket catheter (BC) was introduced transseptally in the PVs. After creating a circumferential ablation line around the PV ostia using a nonfluoroscopic 3D-navigation system, electrical isolation was achieved in 46% of the PVs, and prolongation of conduction time (+39 +/- 34 ms) was observed in 30%. PVs with persistent conduction (54%) were isolated by ablating the remaining conduction pathways using the BC. At 12 months follow-up, 62% of the patients were in stable sinus rhythm without antiarrhythmic drug therapy. Six patients had developed left atrial flutter. CONCLUSIONS: Anatomically guided, circumferential lesions around the PV ostia resulted in isolation in only 46% of the veins. At 12 months, 62% of the patients were free of AF without antiarrrhythmic drug treatment, however, 6 patients (18%) developed left atrial flutter.     

Predictors of recurrence following catheter ablation of atrial fibrillation using an irrigated-tip ablation catheter

INTRODUCTION: The aims of this study were to identify predictors of recurrence after catheter ablation of atrial fibrillation (AF) and to report the safety and efficacy of catheter ablation of AF using an irrigated-tip ablation catheter. METHODS AND RESULTS: Seventy-five consecutive patients (51 men [68%]; age 54 +/- 13 years) with symptomatic drug-refractory paroxysmal (42 patients), persistent (21 patients), or permanent (12 patients) AF underwent catheter ablation of AF using an irrigated-tip ablation catheter and a standard ablation strategy, which involved electrical isolation of all pulmonary veins (PVs) and creation of a cavotricuspid linear lesion. At 10.5 +/- 7.5 months of follow-up following a single (n = 75) or redo ablation procedure (n = 11), 39 (52%) of the 75 patients were free of AF, 10 were improved (13%), and 26 had experienced no benefit from the ablation procedure (35%). Seventy-six percent of patients with paroxysmal AF were free from recurrent AF. The most significant complications were two episodes of pericardial tamponade, mitral valve injury in one patient, two strokes, and complete but asymptomatic PV stenosis in one patient. Cox proportional hazards multivariate regression analysis identified the presence of persistent AF, permanent AF, and age >50 years prior to the ablation are the only independent predictors of AF recurrence after the first PV isolation procedure. CONCLUSION: Catheter ablation of AF using a strategy involving isolation of all PVs and creation of a linear lesion in the cavotricuspid isthmus using cooled radiofrequency energy is associated with moderate efficacy and an important risk for complications. The best results of this procedure are achieved in the subset of patients who are younger than 50 years and have only paroxysmal AF.     

Complete pulmonary vein isolation guided by three-dimensional electroanatomical mapping for the treatment of paroxysmal atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy.

AIMS: Evaluation of the clinical outcome of patients with hypertrophic obstructive cardiomyopathy (HOCM) and paroxysmal atrial fibrillation (AF) treated with complete pulmonary vein (PV) isolation guided by three-dimensional (3-D) electroanatomical (EA) mapping. METHODS: Circumferential radiofrequency (RF) ablation and continuous circular lesions (CCLs) around the left and right-sided PVs were performed in 4 highly symptomatic patients (2 males; age 57.5 +/- 8.3 years) with HOCM and anti-arrhythmic drug (AAD) refractory paroxysmal AF. Ablation was guided by 3-D EA mapping combined with conventional circumferential PV mapping. The endpoints of the ablation were defined as: (1) absence of all PV spikes documented with the two Lasso catheters within the ipsilateral PVs; and (2) no recurrence of the PV spikes within all PVs following intravenous administration of adenosine. RESULTS: The ablation endpoints were achieved in all patients. A repeat ablation was performed in one patient due to repetitive atrial tachycardia, 1 month after the initial procedure. During a follow-up of 5.8 +/- 2.7 months, all patients are free of AF recurrence. Short episodes of symptomatic AT were documented after the repeat procedure, and were well controlled with oral amiodarone in the patient. No procedure-related complications were observed. CONCLUSION: The present study demonstrates that complete isolation of ipsilateral PVs guided by 3-D EA mapping is potentially effective for the treatment of highly symptomatic, drug refractory paroxysmal AF in patients with HOCM.     

Robot-assisted epicardial ablation of the pulmonary veins: is a completed isolation necessary?

AIMS: To study the feasibility and electrophysiological efficacy of minimally invasive beating heart ablation of the pulmonary veins (PVs) via a robot-assisted single-sided approach. BACKGROUND: PV isolation by minimally invasive epicardial ablation may offer a new treatment for patients with lone atrial fibrillation (AF). However, complete PV isolation has been shown to be difficult to obtain. METHODS AND RESULTS: In 14 mongrel dogs, robot-assisted epicardial microwave ablation was performed on the beating heart by a single-sided right chest approach. Isolation of all PVs was performed in two steps to study the effect of an incomplete and a complete isolation on AF. AF was studied by random and burst pacing. Incremental pacing was performed to study conduction characteristics across the lesions. Opening of the pericardial reflections, introduction of the catheter and ablation were robotically feasible by a single-sided approach in 11 dogs. The AF duration decreased from 6.6+/-4.1 to 1.3+/-0.8 s (P=0.03) and 1.6+/-1.6 s (P=0.04 compared with control) after incomplete and completed isolation of the PVs. The AF cycle length increased from 134+/-5 to 141+/-5 and 145+/-8 ms (P=0.03) after incomplete and complete isolation, respectively. Several incomplete lesions showed 2:1 exit and/or entrance block during incremental pacing. After complete isolation, AF was no longer inducible from the PVs. CONCLUSION: Epicardial PV isolation can be successfully performed by a single-sided robot-assisted approach. The effect of PV ablation on AF is not an all or none phenomenon. Incomplete isolation already decreases AF duration and lengthens the AF cycle length. However, complete isolation is necessary to prevent AF induction by triggering from the isolated area.     

Utility of exit block for identifying electrical isolation of the pulmonary veins

INTRODUCTION: Electrical isolation of the pulmonary veins (PVs) to treat paroxysmal atrial fibrillation (AF) has been described using "entry block" as an endpoint for PV isolation. We describe a new technique for guiding PV isolation, using "exit block" out of the PV after ablation as a criterion for successful isolation. METHODS AND RESULTS: A circular mapping catheter was positioned at the os of arrhythmogenic PVs and ablation was performed proximal to the mapping catheter until entry block into the vein was achieved. Pacing was performed from the mapping catheter and from the ablator inside the PV to document exit block out of the PV. In patients in whom cardioversion did not restore sinus rhythm, PV isolation was performed in AF. Entry and exit block were reassessed in ablated veins after a 20-minute waiting period. Ninety-five PVs were ablated in 41 patients. A total of 66 PVs in 34 patients were ablated in sinus rhythm. After entry block was achieved, exit block was present in only 38 (58%) of 66 PVs. A total of 29 PVs in 21 patients were ablated in AF. After cardioversion to sinus rhythm, there was evidence of entry block into the PV in 20 (69%) of 29 PVs and exit block in only 14 (48%) of 29 PVs. There was no significant difference between the total number of lesions applied per vein in sinus rhythm compared with AF (11.6 +/- 8.6 vs 10.3 +/- 6.2; P = NS). There was recovery of conduction after a 20-minute waiting period in 9 (11%) of 84 PVs. CONCLUSION: Identification of exit block after ostial PV ablation provides a clear endpoint for electrical isolation of the PVs. Isolation of the PVs can be performed during sustained AF without the need to apply excess RF lesions. Applying a 20-minute waiting period after electrical isolation will identify reconnection in approximately 10% of PVs.     

Favorable effect of pulmonic vein isolation by partial circumferential ablation on ostial flow velocity

OBJECTIVES: The aim of this study was to determine the effect of electrical isolation of pulmonic vein (PV) on flow velocity. BACKGROUND: We report our experience with electrical isolation of PV by partial circumferential ablation and its effect on ostial peak flow velocity as assessed by phased-array ultrasound catheter imaging. METHODS: Sixty-two patients participated in the study. Magnetic electroanatomic mapping, ultrasound catheter imaging, and Lasso mapping catheter were used. Electrical isolation was achieved by delivering radiofrequency ablation (RFA) lesions proximal to Lasso mapping catheter bipoles showing PV entry. Following this, the number of RFA lesions/PV and their segment-wise distribution (maximum 4/PV) were assessed. RESULTS: Fifty right superior, 51 left superior, 32 left inferior, and 17 right inferior PVs were isolated. RFA involved 4 segments in 42 PVs, 3 segments in 61 PVs, and 90% reduction in AF burden, either with or without previously ineffective antiarrhythmic agents, was achieved in 54 patients (87%). CONCLUSIONS: In the majority of PVs (72%), electrical isolation can be achieved by partial circumferential ablation (targeting 相似文献   

Electrophysiologically guided pulmonary vein isolation during sustained atrial fibrillation

INTRODUCTION: Sustained atrial fibrillation (AF) is frequently encountered during pulmonary vein (PV) isolation. The aim of this study was to evaluate the feasibility and safety of PV isolation during sustained AF. METHODS AND RESULTS: Thirty-seven patients (30 men, age 54 +/- 10 years) underwent Lasso-guided isolation of 87 PVs during sustained AF. Baseline PV electrogram patterns were classified into one of two types: organized, with consistent PV activation sequence; or disorganized, with constant variation of PV activation sequence. In disorganized activity, radiofrequency ablation was performed circumferentially around the Lasso while the earliest PV potential was targeted during organized activity. Complete left atrial (LA) to PV block during AF was identified by abolition or dissociation of all sharp potentials recorded within the vein. PV isolation then was verified during sinus rhythm. Baseline activation patterns of PV potential were organized in 32 PVs (37%) [more frequently in inferior veins than superior veins (53% vs 26%, P = 0.01)] and disorganized in 55 PVs (63%). In 59 of 87 PVs, isolation was begun and completed during AF. Radiofrequency ablation organized PV activation sequence in 75% prior to isolation. LA-PV block was confirmed during sinus rhythm in 54 (92%) of 59 PVs. In 28 of 87 PVs, sinus rhythm was restored before complete LA-PV block. Complete isolation was achieved in all 87 PVs without complications. CONCLUSION: PV isolation can be effectively and safely performed during sustained AF, preceded in most cases by organization of PV electrogram activity. This strategy may be the preferred alternative to multiple intraprocedural cardioversions.     

Effectiveness of catheter ablation for coexisting atrial fibrillation and atrial flutter

In 79 consecutive patients (51 men and 28 women) with paroxysmal (n = 54) or persistent atrial fibrillation (AF) (n = 25) and typical, isthmus-dependent atrial flutter (AFl), pulmonary vein (PV) isolation and anatomically guided linear ablation of the right atrial isthmus was performed during the same procedure. After 208 +/- 331 days of follow-up, 42% remained free of AF and AFl, and a symptomatic lessening was reported by 77%. Paroxysmal AF (beta = 1.682, p = 0.008) and ablation of 3 or 4 PVs (beta = 1.830, p = 0.013) were independent predictors for arrhythmia-free survival. Combined catheter ablation of PVs and the right atrial isthmus for the treatment of patients with mixed AF and AFl is moderately effective in preventing early arrhythmia recurrence but leads to clinical improvement in most patients.     

Long-term safety and efficacy of circumferential ablation with pulmonary vein isolation

Background: Each of the two main approaches to catheter ablation of atrial fibrillation (AF, segmental and circumferential) is associated with moderate long-term efficacy.
Objective: To report the long-term outcomes of a modified technique that combines circumferential ablation with pulmonary vein (PV) isolation, determined by a circular mapping catheter and to determine the relationship between complete PV isolation and long-term efficacy.
Methods: The patient population was composed of 64 consecutive patients (47 men [73%]; age 59 ± 11 years) with AF who underwent catheter ablation. AF was paroxysmal in 29 (45%) and nonparoxysmal in 35 (55%). Each patient was followed for a minimum of 12 months.
Results: After a mean follow-up of 13 ± 1 months, the long-term single-procedure success rate was 45% (n = 29) with an additional 4% (n = 3) of patients demonstrating improvement. With repeat procedures in 19 patients, the overall long-term success rate was 62% (n = 40) with 9% (n = 6) demonstrating improvement. All the patients who underwent repeat ablations had recovered PV conduction. Incomplete PV isolation was the only independent predictor of failure. A major complication occurred in four (6%) patients, including three patients with vascular complications and one with cardiac tamponade.
Conclusion: Our results suggest that the long-term single-procedure efficacy of circumferential ablation with PV isolation in a cohort of patients with predominantly nonparoxysmal AF approaches 50%. Repeat procedures involving re-isolation of the PVs result in a significant improvement in outcomes. Complete electrical isolation of the PVs has a significant impact on the long-term efficacy of the procedure.     

Pulmonary vein isolation for vagotonic, adrenergic, and random episodes of paroxysmal atrial fibrillation

INTRODUCTION: Based on the clinical history, paroxysmal atrial fibrillation (PAF) may be classified as vagotonic, adrenergic, or random. It is unclear whether pulmonary vein (PV) isolation is equally effective for these types of PAF. METHODS AND RESULTS: Segmental ostial ablation to isolate the PVs was performed in 188 consecutive patients (mean age 53 +/- 12 years) with PAF. Based on the clinical history, PAF was classified as random in 136 patients (72%), adrenergic in 30 (16%), and vagotonic in 22 (12%). Three or four PVs were targeted for isolation in all patients, and successful isolation was achieved in 96% of targeted PVs. At 1-year follow-up, 69% of patients with random AF, 83% of patients with adrenergic AF, and 50% of patients with vagotonic AF were free from recurrent episodes of AF in the absence of any antiarrhythmic drug therapy. Vagotonic AF was an independent clinical predictor of recurrent AF (P = 0.03). CONCLUSION: PV isolation has a lower efficacy in patients with vagotonic PAF than in patients with adrenergic or random episodes of PAF, suggesting that the PVs less often play an important role in vagotonic PAF.     

Intracardiac echocardiography-guided,anatomically based radiofrequency ablation of focal atrial fibrillation originating from pulmonary veins

OBJECTIVES: In patients with a pulmonary vein (PV) source for atrial fibrillation (AF), we sought the use of intracardiac echocardiography (ICE) to evaluate PV anatomy, guide radiofrequency (RF) ablation and monitor for acute stenosis during ablation. BACKGROUND: A focal source for AF may be found in the proximal component of the PVs and can be effectively treated by ablative techniques. However, the procedure may be challenging due to the complex anatomy of the left atrium and PVs, uncertain catheter positioning within the PVs and difficulties in mapping atrial extrasystoles, which may be rare or repeatedly induce AF and require cardioversion. METHODS: Sixty-four patients were referred for RF ablation of a focal source of AF, and 56 were identified as having AF triggers in > or =1 PV. Using ICE guidance, RF lesions were applied around the circumference of the vein near the os until there was electrical isolation. RESULTS: Lesions were placed in 82 veins (36 right superior PV, 33 left superior PV, 9 left inferior PV, 4 right inferior PV); 24 +/- 12 lesions per vein were necessary to create electrical isolation with a fluoroscopic time of 11 +/- 4 min and a mean of 22% reduction in luminal area. After a follow-up of 13 +/- 7 months, 66% of patients remained free of AF, and another 13% responded better to medications. CONCLUSIONS: We describe an anatomic approach to PV electrical isolation in which ICE is used to define the anatomy, guide RF ablation and monitor for acute PV changes.     

A single pulmonary vein as electrophysiological substrate of paroxysmal atrial fibrillation

Introduction: It has been demonstrated that pulmonary veins (PVs) play an important role in initiation and maintenance of paroxysmal atrial fibrillation (AF). However, it is not clearly known whether a single PV acts as electrophysiological substrate for paroxysmal AF.
Methods and Results: This study included five patients with paroxysmal AF. All patients underwent complete PV isolation with continuous circular lesions (CCLs) around the ipsilateral PVs guided by a three-dimensional mapping system. Irrigated radiofrequency (RF) delivery was performed during AF on the right-sided CCLs in two patients and on the left-sided CCLs in three patients. The incomplete CCLs resulted in a change from AF to atrial tachycardia (AT), which presented with an identical atrial activation sequence and P wave morphology. Complete CCLs resulted in AF termination with persistent PV tachyarrhythmias within the isolated PV in all five patients. PV tachyarrhythmia within the isolated PV was PV fibrillation from the left common PV (LCPV) in two patients, PV tachycardia from the right superior PV (RSPV) in two patients, and from the left superior PV in one patient. All sustained PV tachyarrhythmias persisted for more than 30 minutes, needed external cardioversion for termination in four patients and a focal ablation in one patient. After the initial procedure, an AT from the RSPV occurred in a patient with PV fibrillation within the LCPV, and was successfully ablated.
Conclusion: In patients with paroxysmal AF, sustained PV tachyarrhythmias from a single PV can perpetuate AF. Complete isolation of all PV may provide good clinical outcome during long-term follow-up.     

Effects of left atrial ablation of atrial fibrillation on size of the left atrium and pulmonary veins

OBJECTIVES: The purpose of this study was to determine the effect of left atrial circumferential ablation on the size of the left atrium and pulmonary veins (PVs). BACKGROUND: The long-term effects of left atrial circumferential ablation on left atrial and PV size and anatomy have not been analyzed in quantitative fashion. METHODS: PV and left atrial sizes were analyzed in 41 consecutive patients (mean age 54 +/- 12 years) with paroxysmal (n = 25) or chronic (n = 16) atrial fibrillation. Computed tomography of the chest with three-dimensional reconstruction was performed before and 4 +/- 2 months after left atrial circumferential ablation. Left atrial circumferential ablation was performed to encircle the PVs 1 to 2 cm from the ostia, using a power output of 70 W. Additional ablation lines were created in the posterior left atrium and mitral isthmus. Radiofrequency energy also was delivered within the circles and at the PV ostia in 51% of patients at a reduced power output of 35 W. RESULTS: At 6 months, 36 patients (88%) were in sinus rhythm without antiarrhythmic drug therapy, including 3 patients (7%) who developed persistent left atrial flutter and underwent subsequent successful ablation of atrial flutter. There was a 15 +/- 16% decrease in left atrial volume (P < .01) and 10 +/- 35% decrease in PV ostial area (P < .01), without focal narrowing, in patients with a successful outcome. Focal PV stenosis did not occur in any of the 41 patients. CONCLUSIONS: Maintenance of sinus rhythm after left atrial circumferential ablation is associated with reduced left atrial and PV ostial size. Left atrial circumferential ablation for atrial fibrillation does not cause PV stenosis.