Pulmonary vein antrum not always coaxial to the pulmonary vein: a dimensional pitfall to the circumferential isolation technique.

BACKGROUND: The dimensions and electrophysiological characteristics of the antral region of human pulmonary veins (PVs) were investigated. METHODS AND RESULTS: Fifty-five consecutive patients with symptomatic paroxysmal atrial fibrillation underwent PV isolation targeting the PV antrum potentials with a 31 mm multielectrode basket catheter (MBC). The most distal and proximal electrode pairs along the MBC spline where radiofrequency ablation was carried out were identified and the longitudinal distance between those ablation sites (Ld) was measured. When the Ld was > or =6 mm, the PV antrum was defined as noncoaxial. In 56% of the left superior PVs, 42% of the right superior PVs, 63% of the left inferior PVs and 56% of the right inferior PVs, a noncoaxial PV antrum was identified. In each PV, the radiofrequency ablation delivery duration and energy to complete the PV antrum isolation were significantly larger in the PVs with a noncoaxial PV antrum than in those with a coaxial PV antrum. CONCLUSION: The PV antrum is noncoaxial to the PV in >50% of the PVs, a feature that may increase the complexity of the circumferential isolation technique.     

Distribution of electrical reconnection after pulmonary vein isolation using a duty-cycled radiofrequency circular ablation catheter

BackgroundCircular ablation catheters (PVAC) have been shown to be effective in the treatment of patients with paroxysmal atrial fibrillation (PAF). The electrophysiological characteristics of the pulmonary veins (PVs) during repeat procedures remain unknown.ObjectiveTo assess the efficacy of PV isolation (PVI) using PVAC and to determine the typical sites of electrical reconnection (ER) of PVs.Methods79 patients with PAF underwent PVI using PVAC. Those who remained symptomatic underwent repeat procedure using a high-density 3D electroanatomical mapping to determine the sites of ERs.ResultsIn total, AF recurrence was documented in 33 patients (41.7%) during the mean follow-up of 1427±378 days. Twenty-two patients had a further ablation. ER of at least one PV was found in all patients. Left upper, left lower, left common, right upper and right lower PV showed ER in 15, 13, 3, 13 and 12 patients, respectively. There was no difference in the number of ERs between individual PVs. In the left upper and left lower PV, 91.7% and 87.5% of gaps, respectively, were localized on the lateral ridge or carina. Sites of ER in the right upper PV were clustered either in the posterior superior (75%) or in the anterior inferior (25%) quadrants of the vein. Reconnection sites in the right lower PV were scattered equally around its whole circumference.ConclusionTypical sites of PV ER are carina and the lateral ridge of the left PVs and superior-posterior aspect of the right upper PV, whereas right lower PV seems to have no typical “reconnection profile”.     

Comparison of 2 mapping strategies for pulmonary vein isolation.

BACKGROUND: Pulmonary vein (PV) isolation using a circular catheter (CC) creates an entrance block from the left atrium (LA) to PV to eliminate paroxysmal atrial fibrillation (PAF). We describe a new approach for PV isolation during distal PV pacing using a basket catheter (BC). The purpose of the present study was to compare 2 mapping strategies for PV isolation. METHODS AND RESULTS: Of 100 consecutive patients with PAF, 50 underwent CC-guided PV isolation and 50 underwent BC-guided PV isolation. During CC-guided ablation, the endpoint was the elimination of PV potentials based on the entrance block from the LA to PV. During BC-guided ablation during distal PV pacing, the endpoint was the elimination of bidirectional PV-LA conduction. At 12 months, 62% of patients who underwent CC ablation and 80% of patients who underwent BC ablation were free of symptomatic PAF without the use of antiarrhythmic drugs (p<0.05). The incidence of mild (<50%) PV stenosis in BC ablation was significantly lower than that in CC ablation (12 vs 24%, p<0.01). CONCLUSIONS: This new approach for PV isolation during distal PV pacing using BC is useful for confirming a bidirectional PV-LA conduction block and is more effective than CC ablation.     

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.     

Left atrial and pulmonary vein macroreentrant tachycardia associated with double conduction gaps: a novel type of man-made tachycardia after circumferential pulmonary vein isolation.

BACKGROUND: The macroreentrant tachycardia that involves the left atrium (LA) and the pulmonary veins (PVs) after atrial fibrillation (AF) ablation has not been described. OBJECTIVE: To clarify the mechanism and electrophysiological characteristics of this tachycardia. METHODS AND RESULTS: Eight patients presented with recurrent regular tachycardia after the initial procedure, which consisted of two circular linear lesions around the ipsilateral PVs. Clinical tachycardia with a cycle length of 297 +/- 38 ms presented as persistent in six and paroxysmal in two patients. During tachycardia, PV activation with one-to-one conduction from the LA to the PV was found via recovered conduction gaps in the previous lesions in all patients. Three-dimensional tachycardia mapping showed a macroreentrant pattern in two and a focal pattern in six patients. In two patients, mapping demonstrated an isthmus within the left common PV in one patient and within the right-sided PVs in another patient. In the remaining six patients with focal pattern, mapping demonstrated earliest atrial activation near the right-sided PV ostium in five patients and near the left-sided PV in one patient. Entrainment mapping showed that the LA and PVs were involved in the reentrant circuit with an isthmus between the two conduction gaps in all eight patients. The tachycardias were successfully terminated with a single radiofrequency application. No AT recurred during follow-up (12 +/- 9 months) in all patients. CONCLUSIONS: The LA-PV macroreentrant tachycardia involves the LA, PV, and the two conduction gaps in the previous lesions. Entrainment mapping is necessary to make the diagnosis. Ablation of this tachycardia can be facilitated by closing the conduction gaps.     

Is circumferential pulmonary vein isolation preferable to stepwise segmental pulmonary vein isolation for patients with paroxysmal atrial fibrillation?

BACKGROUND: Stepwise segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) have been developed to treat patients with atrial fibrillation (AF), but the preferable approach for paroxysmal AF (PAF) has not been established. METHODS AND RESULTS: One hundred and ten patients with symptomatic PAF were randomized into a stepwise SPVI group (n=55) or CPVI group (n=55). Systemic SPVI combined with left atrial linear ablation tailored by inducibility of AF was performed in the stepwise SPVI group. Circumferential linear ablation around the left and right-sided pulmonary veins (PVs) guided by 3-dimensional electroanatomic mapping was performed in the CPVI group. The endpoints of ablation are non-induciblity of AF in the stepwise SPVI group and continuity of circular lesions combined with PV isolation in the CPVI group. After the initial procedures, atrial tachyarrhythmis (ATa) recurred within the first 3 months in 23 of the 55 patients (41.8%) who underwent stepwise SPVI and in 20 of the 55 patients (36.4%) who had CPVI (p=0.69). Repeat procedures were performed in 7 patients from the stepwise SPVI group and 5 from the CPVI group (p=0.76). During the 3-9 months after the last procedure, 46 patients (83.6%) from the CPVI group and 43 (78.2%) from the stepwise SPVI group did not have symptomatic ATa while not taking anti-arrhythmic drugs (p=0.63). Severe subcutaneous hematoma or PV stenosis occurred in 3 patients. CONCLUSIONS: The efficacy of stepwise SPVI is comparable to that of CPVI for patients with PAF.     

Circumferential pulmonary vein isolation: the role of key target sites.

AIMS: Circumferential pulmonary vein isolation (CPVI) had been proved effective for treating atrial fibrillation (AF). However, the achievement of pulmonary vein (PV) isolation was sometimes challenging. PVs could not be isolated until some key target sites (KTSs) were ablated thoroughly. The aim of our study was to explore the distribution of KTSs. METHODS AND RESULTS: Four hundred and fifty-two cases (271 males, mean age 62.5 +/- 12.6 years) with drug-refractory AF were enrolled for catheter ablation. CARTO-guided CPVI was performed in all cases with one circular catheter for verification of PVs isolation. Target sites where PV potentials delayed, conduction sequence changed, slowed down, or isolated were defined as KTSs. From 452 CPVI procedures, 1520 KTSs were identified; 813 of which were located at left PV antrums and 707 were at right PV antrums. KTSs at left PV antrums were most commonly situated at anterior wall (63%), while KTSs at right PV antrums were most commonly situated at posterior wall (66.2%). Additional gaps ablation was performed for left PVs in 344 cases and for right PVs in 248 cases owing to incomplete PVs isolation by a single attempt of CPVI. One thousand one hundred and fifty-eight KTSs were identified, 662 of which were located at left PV antrums and 496 were at right PV antrums. At the anterior wall, 66.1% of left PV KTSs were located, and 67.9% of right PV KTSs were located at the posterior wall. Out of 1158, 961 (82.99%) KTSs were predicted correctly by circular mapping. PV isolation could not be achieved until some KTSs were ablated by higher power, longer duration, and higher irrigation rate than usual. CONCLUSION: KTSs during CPVI were most commonly situated at the anterior wall of left PVs and at the posterior wall of right PVs. Circular mapping within ipsilateral PVs' ostia could accurately predict the location of KTSs. Some KTSs must be ablated thoroughly by applying higher power, longer duration, and higher irrigation rate than usual to achieve PV isolation.     

阵发性心房颤动节段性肺静脉电隔离方法学评价

目的评价经改良的节段性电隔离肺静脉方法治疗阵发性心房颤动的有效性及安全性.方法 39例阵发心房颤动患者,男性28例,女性11例,采用一次房间隔穿刺技术,送入标测及消融电极,并选用猪尾造影导管用高压非选择性造影显示肺静脉开口及左心耳位置,指导导管行进方向以减少心脏压塞风险.标测中常规探查、标测右下肺静脉,避免遗漏可能触发心房颤动的肺静脉电位.在肺静脉电位优势传导部位消融并轻微移动形成节段性电隔离.结果单个节段或多个节段消融可使肺静脉与左心房之间形成完全性电隔离.节段性隔离靶肺静脉85根,即刻成功81根,成功率95%,无并发症发生.结论节段性电隔离肺静脉法可有效隔离肺静脉,与其他传统方法比较,手术时间短、成功率高,可减少肺静脉的损伤和避免肺静脉狭窄的发生.     

Pulmonary vein isolation to treat paroxysmal atrial fibrillation: conventional versus multi-electrode radiofrequency ablation

Purpose

For patients with symptomatic atrial fibrillation (AF), a curvilinear multi-electrode ablation (MEA) catheter has been reported to be successful to achieve pulmonary vein (PV) isolation. However, this approach has not been compared prospectively with conventional PV isolation (CPVI) using a standard circular mapping catheter and 3D electro-anatomic mapping. In this prospective non-randomized study, we compared the efficacy of these two techniques.

Methods

Of 185 consecutive patients, age 54.6?±?10.1?years, with symptomatic paroxysmal AF (PAF), 96 patients underwent PV isolation by CPVI and 89 patients underwent MEA to isolate the PVs. CPVI was performed by encircling the left- and right-sided PVs. During MEA, the PV ablation catheter (Medtronic, USA) was used to isolate PVs with duty-cycled radiofrequency energy.

Results

The mean procedure time was 171.73?±?52.87?min for CPVI and 133.25?±?37.99?min for MEA, respectively (P?P?=?0.651). At 12?months, 80% of patients who underwent CPVI and 82% of patients who underwent MEA were free of symptomatic PAF off antiarrhythmic drug therapy (P?=?0.989). Among the variables of age, gender, duration and frequency of PAF, left ventricular ejection fraction, left atrial size, structural heart disease, and the ablation technique, only an increased left atrial size was an independent predictor of recurrent PAF. Left atrial flutter occurred after CPVI in two patients and after MEA ablation in three patients.

Conclusion

In patients undergoing catheter ablation for PAF, MEA and CPVI proved equally efficacious.     

New approach to pulmonary vein isolation for atrial fibrillation using a multielectrode basket catheter.

BACKGROUND: Pulmonary vein (PV) isolation using a circular catheter creates an entrance block from the left atrium (LA) to the PV, which eliminates paroxysmal atrial fibrillation (PAF). A new approach to PV isolation during distal PV pacing is to use a basket catheter. METHODS AND RESULTS: Fifty consecutive patients with PAF underwent basket-catheter-guided PV isolation. PV pacing was performed from the distal electrode pair of the basket catheter. The exit breakthrough point was targeted for segmental PV isolation. The endpoint was the elimination of bidirectional PV - LA conduction. A repeat ablation procedure was performed in 12 of 14 patients who had recurrence of AF. The recovery of PV -LA conduction was noted in 24 of the 48 PVs, and 5 PVs (21%) had unidirectional block. At 12 months, 80% of patients were free of AF without antiarrhythmic drugs. No PV stenosis >50% was detected at 12 months after the procedure. CONCLUSIONS: This new approach for PV isolation during distal PV pacing using a basket catheter is useful for confirming bidirectional PV - LA conduction block. PV isolation that creates not only an entrance block but also an exit block at the PV - LA junction may be required to cure paroxysmal AF.     

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.     

Mechanisms of recurrent atrial fibrillation after pulmonary vein isolation by segmental ostial ablation

OBJECTIVES: The aim of this study was to determine the mechanisms responsible for recurrent atrial fibrillation (AF) after pulmonary vein isolation (PV) by segmental ostial ablation. BACKGROUND: Recovery of conduction into a previously isolated PV is a common observation when there is recurrent AF soon after segmental ostial ablation. However, the mechanisms of recurrent AF have been unclear. METHODS: A repeat ablation procedure was performed in 50 patients who had recurrent paroxysmal AF at a mean of 7 +/- 6 months after segmental ostial ablation to isolate the PVs. During the repeat procedure, a ring catheter was inserted into each PV during sinus rhythm and AF to determine whether the veins were still isolated and, if not, whether there were PV tachycardias with a cycle length shorter than in the adjacent left atrium during AF. RESULTS: There was recovery of conduction over a previously ablated muscle fascicle in >/=1 PV in 49 patients (98%). There were 10 +/- 2 episodes of PV tachycardia per minute in 36 (72%) of the 50 patients during AF. Repeat ablation was performed by segmental ostial ablation (23 patients) or by left atrial catheter ablation to encircle the left- and right-sided PVs 1 to 2 cm from the ostia, with additional ablation lines in the posterior left atrium and mitral isthmus (27 patients). At 6-month follow-up, among 23 patients who underwent repeat ablation by segmental ostial ablation, AF recurred in 4 (21%) of the 19 patients who had PV tachycardias and in 3 (75%) of the 4 patients who did not (P = .03). Among the 27 patients who underwent left atrial ablation, AF recurred in 2 (12%) of the 17 patients who had PV tachycardias and in 1 (10%) of the 10 patients who did not (P = 0.7). CONCLUSIONS: Recovery of conduction in previously ablated muscle fascicles is a common finding in patients with recurrent AF after segmental ostial ablation. The efficacy of repeat segmental ostial ablation depends on the presence of PV tachycardias, whereas left atrial ablation is effective regardless of whether PV tachycardias are present or not during 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.     

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.     

Incidence and location of focal atrial fibrillation triggers in patients undergoing repeat pulmonary vein isolation: implications for ablation strategies

INTRODUCTION: The etiology of atrial fibrillation (AF) recurrences after pulmonary vein (PV) isolation is not well described. The aim of this study was to examine the reason for recurrent AF in patients undergoing a repeat attempt at AF trigger ablation. METHODS AND RESULTS: Patients with recurrent AF more than 1 month after ablation returned for repeat mapping and ablation. A circular mapping catheter was advanced to each previously targeted PV ostium to determine if the PV was still electrically isolated. Ectopy then was provoked with isoproterenol (up to 20 microg/min), burst pacing, and pacing into AF followed by cardioversion. The location of ectopy triggering atrial premature depolarizations (APDs) or AF was noted. Of 226 patients who underwent ablation of AF triggers, 34 (8 women and 26 men; age 56 +/- 10 years) with recurrent AF returned for a repeat procedure 207 +/- 183 days after the first procedure. There were 84 previously completely isolated PVs in these 34 patients. Thirty-three (39%) of 84 previously isolated PVs were still completely isolated at the time of the second procedure. Fifty-one PVs (61%) had evidence of recovered PV potentials. Fifty triggers of APDs and AF (n = 30) or APDs only (n = 20) were identified in these 34 patients. The majority of triggers [27/50 (54%)] originated from previously targeted PVs. Sixteen triggers [16/50 (32%)] originated from previously nontargeted PVs. CONCLUSION: The majority of AF recurrences originate from previously isolated PVs. One third of recurrent triggers originated from PVs that were not targeted during the initial ablation session. Although empiric isolation of all PVs may reduce recurrences, strategies to ensure ostial PV isolation and to prevent recurrent PV conduction after ablation should have the greatest impact on reducing AF recurrence.     

Efficacy and safety of segmental ostial versus circumferential extra-ostial pulmonary vein isolation for atrial fibrillation

INTRODUCTION: Pulmonary vein (PV) isolation for atrial fibrillation (AF) can be performed using a segmental ostial or a circumferential extra-ostial approach. The relative merits and potential limitations of each approach are currently debated. Here we report our early experience with each of these approaches, including their relative efficacy and safety. METHODS AND RESULTS: Forty patients with drug-refractory AF underwent segmental ostial PV isolation and were compared to 40 consecutive patients who underwent PV isolation using a circumferential extra-ostial approach. The latter approach described here is novel in two aspects: (1) the endpoint for ablation was PV isolation and not only delay in left atrial to PV conduction time, and (2) isolation of the right and left PVs was achieved by a single encirclement of ipsilateral veins. At follow-up, 60% of the patients in the segmental group were free of AF compared to 75% of the patients in the circumferential group. There was one thromboembolic cerebrovascular complication during the ablation procedure in each group. CONCLUSION: PV isolation using a circumferential extra-ostial approach, where the ipsilateral PVs are isolated together by one encircling line of block using electroanatomic mapping, is a technically feasible procedure. This approach is at least as effective and safe as the more established segmental ostial approach for AF ablation.     

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).     

环静脉导管消融术的消融达终点部位分析及相应的策略

目的分析以电隔离为终点的环肺静脉导管消融过程中,消融达终点部位的分布规律,并探讨相应的标测策略和消融技巧。方法入选症状明显、药物治疗无效的心房颤动患者452例。在三维电解剖标测系统(CAR-TO)指导下行导管射频消融,均采用环肺静脉电隔离术为基本术式,使用单个环状电极标测肺静脉电位,消融终点为肺静脉电隔离。在环肺静脉消融过程中,用CARTO标记出消融达终点部位,即肺静脉心房肌束连接部位,通常表现为消融后肺静脉电位明显延迟、频率明显减慢或消失。结果在452例的消融过程中共记录到消融达终点部位1520处,包括环左侧肺静脉813处,最常见于左前上(201处,24.7%)、左前中(180处,22.1%)和左前下(132处,16.2%);环右侧肺静脉707处,最常见于右后中(207处,29.3%)和右后上(162处,22.9%)。所有单圈未隔离而在环肺静脉消融线上补点消融的病例中,961个消融达终点部位(82.99%)与环状电极指示区域一致,通过在消融线上大头仔细标测进一步确定消融达终点部位,并根据不同的部位分别采用增加消融时间、冷盐水灌注的流速以及改变导管贴靠方式等方法可有效地达到肺静脉电隔离的消融终点。结论环静脉导管消融术达到电隔离终点的常见消融达终点部位分布有一定规律,最多见于左侧消融线前壁和右侧后壁,环状电极可有效提示消融达终点部位的大体位置,采用改变导管贴靠方式以及增加消融时间、冷盐水流速等方法可以有效阻断消融达终点部位,达到电隔离终点。     

Efficacy of repeat pulmonary vein isolation procedures in patients with recurrent atrial fibrillation

INTRODUCTION: Pulmonary vein (PV) isolation is effective in the treatment of most patients with atrial fibrillation (AF). Some advocate the addition of linear ablation techniques to improve efficacy; however, previous studies suggest recurrent PV conduction is responsible for AF recurrence. The aim of this study was to determine the effectiveness of repeat PV isolation in patients with recurrent AF after an initial ablation procedure and to determine if any patient characteristics predict failure of repeat PV isolation procedures. METHODS AND RESULTS: Seventy-four patients with two or more AF ablation procedures using selective PV isolation were included. PV isolation was guided with multielectrode ring catheter recordings, electroanatomic mapping, and intracardiac electrocardiography. Radiofrequency energy was delivered using a 4-mm-tip catheter (maximum 40 W, 52 degrees C); cooled-tip ablation was performed in 10 patients. Linear ablation was not performed. Antiarrhythmic drugs were continued for at least 6 weeks after ablation; AF episodes during this period were censored. Reconnection of one or more segments of previously ablated PVs was observed in 97% of patients; reconnected PVs served as the trigger for AF in 77%. Repeat PV isolation resulted in AF control (cure or 90% reduction in AF episodes) in 64 patients (86%) over a follow-up period of 9.1 +/- 6.7 months. "High-risk" characteristics such as left atrial enlargement, persistent AF, or mitral regurgitation did not predict failure of repeat PV isolation procedures. CONCLUSION: Recurrent AF following selective PV isolation is overwhelmingly associated with PV electrical reconnection. Repeat PV isolation without linear ablation provides effective treatment for recurrent AF in patients in whom an initial PV isolation procedure failed, independent of clinical characteristics.     

Mechanisms of recurrent atrial fibrillation: comparisons between segmental ostial versus circumferential pulmonary vein isolation

Background: Electrical isolation of pulmonary veins (PVs) is an effective therapy for atrial fibrillation (AF). Both segmental ostial PV ablation and circumferential ablation with PV–left atrial (LA) block have been implicated to eliminate AF. However, the mechanism of the recurrent AF after undergoing either strategy remains unclear.
Methods and Results: Of the 73 consecutive patients with symptomatic AF that underwent PV isolation and had recurrences of AF, Group 1 consisted of 46 patients (age 56 ± 13 years old, 35 males) who underwent PV isolation by segmental ostial PV ablation and Group 2 consisted of 27 patients (age 51 ± 11 years old, 24 males) who underwent circumferential ablation with PV–LA block. In Group 1, the earliest ectopic beat or ostial PV potentials were targeted. In Group 2, circumferential ablation with PV–LA block was performed by encircling the extraostial regions around the left and right PVs. During the first procedure, all patients had PV–AF. There was no difference in the non-PV ectopy between Group 1 and Group 2. During the second procedure, the incidence of an LA posterior wall ectopy initiating AF was significantly lower (20% vs. 0%, P = 0.01) in Group 2. There was no difference in the PV ectopy initiating AF during the second procedure.
Conclusion: Circumferential ablation of AF with PV–LA block may eliminate the LA posterior wall ectopy and decrease the incidence of LA posterior wall ectopy initiating AF during the second procedure.