阵发性心房颤动患者非肺静脉触发灶的诱发及消融

目的探讨环肺静脉电隔离（CPVI）术中静脉注射异丙肾上腺素（ISO）和三磷酸腺苷：ATP）,在检出阵发性心房颤动（房颤）非肺静脉触发灶中的价值。方法回顾性分析2010年4～12月色浙江邵逸夫医院心内科所有患者接受三维标测系统指导下CPVI术136例患者,其中87例消融前后分别应用ISO＋ATP诱发房颤,Lasso导管置于右上肺静脉口、消融导管置于左上肺静脉中,结合冠状静冰窦导管判断房颤的触发灶,然后通过消融验证。结果87例首次接受导管消融的阵发性房颤患者,吏用ISO＋ATP后16例证实有非肺静脉房颤触发灶。其中,消融前诱发8例房颤、1例房性心动过速（房塞）、1例频发房性早搏（房早）。2例消融前诱发的患者CPVI术后房性快速性心律失常（ATa）仍存在,余8例及5例消融前未被诱发者CPVI后再次诱发时又检出非肺静脉触发灶。其中,9例为房颤（起源上腔静脉5例、冠状静脉窦内靠近口部1例、左心房后壁2例、不明1例）,3例房性心动过速（均为冠状挣脉窦口起源）和1例频发房性早搏（上腔静脉起源）。14例患者在相应非肺静脉触发灶部位消融后心聿失常均终止,且不再被诱发。2例起源不明的房颤患者电复律后转为窦性心律。随访2年,单次手术或功率为87．5％（14／16）。结论静脉注射ISO＋ATP可简单有效地检出阵发性房颤非肺静脉触发灶。     

Identification of pulmonary vein foci by non-contact mapping in patients with paroxysmal atrial fibrillation.

AIMS: Ectopies from the pulmonary veins may cause paroxysmal atrial fibrillation and their discrete ablation may be curative. In the absence of focal activity during the procedure, identification of target sites with conventional techniques is difficult. We investigated the feasibility of non-contact mapping (EnSite) for identification and successful ablation of pulmonary vein foci in such cases. METHODS AND RESULTS: We studied 7 patients with idiopathic paroxysmal atrial fibrillation referred for percutaneous ablation and not presenting spontaneous or inducible atrial premature beats during the procedure. An EnSite balloon catheter and an ablation catheter (NaviStar) were placed inside the left atrium. The ablation catheter was also used for electroanatomic mapping (CARTO) of specific sites. Multiphasic pulmonary vein potentials were detected on virtual electrograms and tagged on the non-contact map and confirmed with conventional mapping. The procedural endpoint was elimination or dissociation of the multiphasic potential. Non-contact mapping identified 13 foci of multiphasic potentials in the seven patients (5 foci were initially identified by EnSite), and discrete ablation suppressed 9 of them (69%). Six months later, 4 of the 5 patients in whom all foci were suppressed remain asymptomatic, in sinus rhythm, under no medication. CONCLUSION: In patients with paroxysmal atrial fibrillation and no ectopic activity during electrophysiological study virtual electrograms may complement conventional techniques in detecting hidden pulmonary vein foci and may be used to evaluate ablation efficacy.     

The superior vena cava as a site of ectopic foci in atrial fibrillation

Radiofrequency catheter ablation of ectopic foci that trigger atrial fibrillation has been established as a curative method for patients with symptomatic paroxysmal atrial fibrillation. Although the majority of these foci are located in and around the pulmonary veins, other less common locations have been identified. Recognition that foci can lie outside the pulmonary veins is important for ensuring therapeutic success. The most frequently reported foci of ectopic activity outside the pulmonary veins are in the superior vena cava and the posterior wall of the left atrium. Here we report our experience with the ablation of ectopic foci located in the superior vena cava in patients with symptomatic paroxysmal atrial fibrillation.     

3-D-Mapping der Pulmonalvenen mit einem multipolaren Basketkatheter

BACKGROUND: Focal discharges from pulmonary veins are the major sources of paroxysmal atrial fibrillation. The aim of this study was to analyze the activation pattern of pulmonary veins during sinus rhythm and ectopy with the help of a multipolar basket catheter and to disconnect them from the left atrium by localized radiofrequency catheter ablation. PATIENTS AND METHODS: We studied 65 patients (43 male, 22 female, mean age 54 +/- 12 years) with drug-refractory atrial fibrillation (paroxysmal n = 42, persistent n = 23). A 64-pole basket catheter (Figure 1) with a diameter of 31 or 38 mm (Constellation, Boston Scientific) was placed transseptally into the pulmonary veins to record its activation during ectopic beats and during sinus rhythm or coronary sinus pacing (Figure 2). The ablation catheter was placed as ostial as possible next to the electrodes showing the earliest pulmonary vein activation during sinus rhythm or coronary sinus pacing (Figures 3 and 4a). The radiofrequency energy was delivered with a maximum temperature of 50 degrees C and a maximum power of 30 W. In 32 patients, an irrigated-tip catheter (Thermocool, Biosense-Webster) was used. Endpoint of the procedure was the complete elimination of all distal pulmonary vein potentials during sinus rhythm (Figure 4b). RESULTS: The mean number of procedures per patients was 1.25, mean procedure time 236 +/- 79 min, and mean fluoroscopy time 40 +/- 17 min, respectively. In 16 veins, repetitive discharges (more than three) could be recorded under stable conditions (Figures 2 and 5). In twelve of these 16 pulmonary veins (75%), the activation pattern during ectopic beats was identical in the same vein, but different from one vein to another (Figure 2). In four veins, changing activation patterns were observed in the same vein. Focal atrial fibrillation was recorded in four pulmonary veins (Figures 6 and 7). A total of 187 out of 190 mapped veins were successfully isolated at the ostium by ablating 2.3 +/- 1.1 separated conduction pathways. In 16 patients, a second EP study was performed for recurrence of atrial fibrillation. Recovery of conduction of a previously isolated pulmonary vein was identified as the primary reason for recurrence of atrial fibrillation. The second reason were ostial foci, localized proximal to the ablation line (Figure 8). COMPLICATIONS AND FOLLOW-UP: One pericardial tamponade occurred. Carbonization on the splines of the basket catheter-observed in twelve cases with use of a nonirrigated-tip catheter-was prevented by use of irrigated-tip catheters. At 12 months, 36 out of 65 patients (55%) are in sinus rhythm without antiarrhythmic drug use, 28 of 42 patients (67%) with paroxysmal atrial fibrillation. Only one pulmonary vein stenosis > 50% was detected by angiomagnetic resonance imaging 1 year after the procedure. CONCLUSION: 75% of the arrhythmogenic pulmonary veins showed a stable and specific pattern during repetitive ectopic activity. Ostial ablation of 2.3 +/- 1.1 separated conduction pathways from the left atrium into the pulmonary veins resulted in complete conduction block in 187 of 190 veins.     

Global distribution of atrial ectopic foci triggering recurrence of atrial tachyarrhythmia after electrical cardioversion of long-standing atrial fibrillation: a bi-atrial basket mapping study.

OBJECTIVES: The objective of this study was to assess the spatial distribution of atrial ectopic foci potentially triggering recurrent atrial tachyarrhythmias after electrical cardioversion of long-standing atrial fibrillation (AF). BACKGROUND: It remains unknown whether targeted ablation of atrial ectopic foci concentrated in the pulmonary veins is feasible in patients with long-standin     

The role of atrial ectopics in initiating paroxysmal atrial fibrillation.

AIMS: To characterize the nature and timing of atrial ectopics preceding clinical episodes of paroxysmal atrial fibrillation. METHODS AND RESULTS: Holter recordings (n= 177, 60 patients, 58% male, mean age 61.7 +/- 11.5 years) were performed on patients with paroxysmal atrial fibrillation. These were subjected to standard analysis and recordings containing atrial fibrillation episodes suitable for analysis were identified (n = 74). Beat interval files differentiating sinus rhythm from atrial fibrillation were generated and atrial ectopics were identified. Atrial ectopics preceding atrial fibrillation were found to be more frequent (5.07 +/- 7.39 min(-1)) and more premature (ratio of coupling interval to that of surrounding sinus cycles = 0.56 +/- 0.08) compared to ectopics occurring remote from atrial fibrillation episodes (frequency = 3.60 +/- 7.32 min(-1) P = 5 x 10(-24), prematurity ratio = 0.60 +/- 0.10, P = 2 x 10(-73)). Atrial ectopic coupling interval frequency histograms were generated and analysed visually and by an automated statistically based test. Many ectopics were seen to occur at one coupling interval in 27 recordings (in eight this occurred only preceding atrial fibrillation onset, while in a further 19 cases this was also seen remote from atrial fibrillation onset). Overall 45% of ectopics preceding atrial fibrillation episodes occurred in isolation, 13% as part of a bigeminal rhythm, 22% as couplets and 20% as runs. This pattern did not differ from that seen remote from atrial fibrillation episodes. CONCLUSION: Paroxysmal atrial fibrillation is preceded by ectopics of a fixed coupling interval in a significant proportion of patients. If, as seems likely, this is a marker of 'focally mediated' atrial fibrillation, then Holter techniques may provide a useful screening tool with which to identify patients suitable for fuller electrophysiological assessment.     

Pulmonary Vein Bigeminy: Electrophysiological Characteristics and Results of Catheter Ablation

Pulmonary vein bigeminy is the pair of a second, late and ectopic pulmonary vein potential following atrial far-field activation and a first passive pulmonary vein potential during sinus rhythm. The aim of this study was to determine the electrophysiological characteristics of pulmonary vein bigeminy and to evaluate its relevance as a trigger for paroxysmal atrial fibrillation. Methods and Results: Pulmonary vein bigeminy was recorded in 8 of 45 patients (18%) who underwent mapping of pulmonary veins for ablation of focal atrial fibrillation. The premature ectopic pulmonary vein potentials were conducted to the atria in 5 patients and were not conducted (concealed bigeminy) in 3 patients. The coupling interval of the ectopic pulmonary vein potential to the preceding atrial signal during sinus rhythm was significantly longer in patients with conducted bigeminy (375 ± 25 ms) than with concealed bigeminy (230 ± 17 ms). The pulmonary vein bigeminy was driven by coronary sinus pacing with the pacing cycle length at lower stimulation rates and was suppressed by overdrive pacing. Coronary sinus pacing led to a separation of the first pulmonary vein potential from the atrial signal but the interval between the atrial signal and the second pulmonary vein potential remained unchanged. Focal ablation at the site of earliest ectopic pulmonary vein activity in 5 patients induced rapid repetitive firing before elimination of the pulmonary vein bigeminy. Ostial disconnection of the arrhythmogenic pulmonary vein in 3 patients was associated with elimination of the pulmonary vein bigeminy. During the follow-up of 9 ± 5 months after ablation of the pulmonary vein bigeminy, 5 of the 8 patients (63%) were free of atrial fibrillation without antiarrhythmic medication. Conclusions: The response of pulmonary vein bigeminy to atrial pacing and ostial ablation suggests that pulmonary vein bigeminy depends on an intact electrophysiological breakthrough between the left atrium and the pulmonary vein. Ablation targeting the pulmonary vein bigeminy is a possible limited approach for this subgroup of patients with paroxysmal atrial fibrillation.     

Pulmonary vein dimensions and variation of branching pattern in patients with paroxysmal atrial fibrillation using magnetic resonance angiography

Pulmonary veins are the most frequent origin of focal and paroxysmal atrial fibrillation. Although radiofrequency ablation has been attempted for the treatment of focal and paroxysmal atrial fibrillation, the anatomy of the pulmonary vein is still not fully understood. To investigate the dimensions and anatomical variation of the pulmonary vein in patients with paroxysmal atrial fibrillation, we performed breath-hold gadolinium enhanced magnetic resonance (MR) angiography using a 1.5 T cardiac MR imager (GE CV/i) in 32 patients with paroxysmal atrial fibrillation (61 +/- 8 years old), 11 patients with chronic atrial fibrillation (64 +/- 9 years old), and 26 patients with normal sinus rhythm (55 +/- 15 years old). Three dimensional images of the pulmonary veins were thus obtained, and the diameters of the most proximal portion of the left or right superior pulmonary vein and left or right inferior pulmonary vein were measured. Pulmonary vein branching variations were determined by a visual qualitative analysis by two separate readers' agreements, who were blinded to any clinical information. We focused on the existence of a complex-branching pattern draining into the orifice of four pulmonary veins. Patients with either paroxysmal atrial fibrillation or chronic atrial fibrillation showed larger superior pulmonary veins than those with normal sinus rhythm (mean +/- SD; in the left superior pulmonary vein, 20 +/- 3 mm, 23 +/- 3 mm vs 16 +/- 3 mm, P < 0.05; in right superior pulmonary vein, 19 +/- 4 mm, 19 +/- 2 mm vs 16 +/- 2 mm, P < 0.05). Complex-branching pattern was frequently observed in inferior pulmonary veins in patients with either paroxysmal atrial fibrillation or chronic atrial fibrillation; 25/32 patients with paroxysmal atrial fibrillation, 11/11 patients with chronic atrial fibrillation, compared to 7/26 patients with normal sinus rhythm. Complex-branching patterns were not observed in superior pulmonary veins in any patients in this cohort. CONCLUSION: In patients with paroxysmal atrial fibrillation or chronic atrial fibrillation, significant pulmonary vein dilation occurred mainly in the superior pulmonary veins, while a complex-branching pattern was frequently observed in the inferior pulmonary veins. These MR angiographic findings might be useful when performing radiofrequency ablation procedures and catheter manipulation for the treatment of paroxysmal atrial fibrillation.     

长程持续性房颤消融术中规整房速的处理

目的探索慢性房颤导管消融中规则房速的发生机制与处理方法。方法选择2009年1月至2013年5月在厦门心脏中心确诊并接受导管消融治疗的慢性房颤患者102例,采用递进式导管消融策略,分析慢性房颤患者在消融中发生规则房速的可能机制并进行相应处理。结果102例患者中,4例（4．9％）在肺静脉电隔离过程中转为窦律,3例（2．9％）在行碎裂电位消融时转为窦律,46例经碎裂电位消融及心房线性消融过程中转为规则房速（45．1％）,47例（46．1％）仍维持房颤。规则房速的发生机制为局灶自律性（17．6％）、折返性（77．8％）、其它（4．6％）,消融成功率为81．6％。结论慢性房颤递进式导管消融中,规则房速的发生机制多为大折返性,导管消融此类房速成功率较高。     

Primary catheter ablation in atrial fibrillation

BACKGROUND: Primary catheter ablation of atrial fibrillation is a new and curative option for the treatment of patients with drug-refractory atrial fibrillation. It is aiming at a long-term restoration of sinus rhythm and thereby causing a coordinated atrial contraction. ABLATION METHODS: Two different ablation strategies have been established: The "trigger elimination" tries to identify triggering atrial extrasystoles (mostly within the pulmonary veins), followed by focal ablation or isolation within the pulmonary veins. The "substrate modification" changes by long linear radiofrequency-induced lesions the ability of the atrial myocardium to sustain atrial fibrillation. VALUATION: Both treatment options still have to prove their effectiveness in carefully monitored follow-up, before they can be offered to the general patient population with atrial fibrillation.     

Focal atrial fibrillation treated with radiofrequency

Atrial fibrillation is usually thought to be due to multiple circulating reentrant wavelets. From previous studies, a focal mechanism is considered to be very unlikely. This focal source could be successfully treated by radiofrequency catheter ablation. We report a patient without structural heart disease, but with multiple episodes of syncope and palpitations related to atrial tachycardia and atrial fibrillation. Electrophysiological study demonstrated that all atrial arrhythmias were due to one focus located in the left atrium at the ostium of the left superior pulmonary vein that was successfully treated with the use of a mean of three radiofrequency pulses, without complications. The pulmonary veins are an important source of ectopic beats, initiating frequent paroxysm of atrial fibrillation. These foci respond to treatment with radiofrequency ablation.     

Predictors of atrial rhythm after atrioventricular node ablation for the treatment of paroxysmal atrial arrhythmias

OBJECTIVE: To assess the natural history of the atrial rhythm of patients with paroxysmal atrial arrhythmias undergoing atrioventricular node ablation and permanent pacemaker implantation. DESIGN AND SETTING: A retrospective cohort study of consecutive patients identified from the pacemaker database and electrophysiology records of a tertiary referral hospital. PATIENTS: 62 consecutive patients with paroxysmal atrial arrhythmias undergoing atrioventricular node ablation and permanent pacemaker implantation between 1988 and July 1996. MAIN OUTCOME MEASURES: (1) Atrial rhythm on final follow up ECG, classified as either ordered (sinus rhythm or atrial pacing) or disordered (atrial fibrillation, atrial flutter or atrial tachycardia). (2) Chronic atrial fibrillation, defined as a disordered rhythm on two consecutive ECGs (or throughout a 24 hour Holter recording) with no ordered rhythm subsequently documented. RESULTS: Survival analysis showed that 75% of patients progressed to chronic atrial fibrillation by 2584 days (86 months). On multiple logistic regression analysis a history of electrical cardioversion, increasing patient age, and VVI pacing were associated with the development of chronic atrial fibrillation. A history of electrical cardioversion and increasing patient age were associated with a disordered atrial rhythm on the final follow up ECG. CONCLUSIONS: Patients with paroxysmal atrial arrhythmias are at high risk of developing chronic atrial fibrillation. A history of direct current cardioversion.     

Catheter ablation for atrial fibrillation: clinically established or still an experimental method

Interventional treatment for atrial fibrillation has been introduced as a therapeutic option since the pulmonary veins (PV) have been discovered as the dominant sources of paroxysmal atrial fibrillation (PAF). Elimination of PV conduction is the initial goal during catheter ablation in this setting. The success rate after the initial procedure varies between 60 and 85 %, with more than 80 % after subsequent interventions. Supported by the current guidelines, interventional treatment of AF is indicated in case of symptomatic arrhythmias refractory to antiarrhythmic treatment. The introduction of the combined, stepwise approach has been another important breakthrough with regard to the treatment of chronic persistent atrial fibrillation (CAF). This strategy includes the combination of all conventional ablation strategies (PV isolation, ablation of complex fractionated atrial electrograms, linear ablation) with the goal of AF termination. The first procedure for CAF treatment is quite frequently also only the first step towards stable sinus rhythm with a favourable outcome after AF termination (> 80 % sinus rhythm). In more than half of the patients predominantly other atrial arrhythmias than AF have to be targeted in a second procedure. This approach is currently under clinical investigation and so far not "clinically established" due to the fact that it is a quite time consuming and challenging procedure even in experienced centres. Future studies may help to identify predictors for procedure failure (e.g. LA size, AF duration, atrial cycle length, spectral analysis) in order to improve patient selection. Additionally, it has to be underscored, that in paroxysmal atrial fibrillation the relatively high recurrence rate after the first procedure still is the subject of further investigations. This aspect might be improved by the introduction of novel strategies (i.e. testing of concealed PV conduction after ablation with adenosine) or new technologies (i.e. robotic navigation) for PAF ablation.     

Evaluation of the recurrence of atrial fibrillation after pulmonary venous ablation

OBJECTIVES: The mechanism of the recurrence of atrial fibrillation after pulmonary vein ablation was evaluated. METHODS: Eighty patients with atrial fibrillation underwent pulmonary vein ablation. If extrasystoles or atrial fibrillation initiations were frequent, focal ablation was performed at the site of the earliest activation. If the patient had little or no ectopy, all pulmonary veins with distinct and late pulmonary vein potentials were targeted for pulmonary vein isolation, which was achieved by minimal segmental ablation limited to the ostial site with the earliest pulmonary vein potentials. RESULTS: Focal ablation or pulmonary vein isolation was performed in 42 and 38 patients, respectively. After focal ablation, atrial fibrillation recurred in 23 patients and re-ablation was performed in 10:7 at sites near the previous source, 2 at a different part of the same pulmonary vein, and 1 at a different pulmonary vein. After pulmonary vein isolation, atrial fibrillation recurred in 19 patients and re-ablation was performed in 14:8 due to recovery of atrio-pulmonary vein conduction, 3 at non-pulmonary vein foci, 2 at pulmonary vein ostia proximal to the previous pulmonary vein isolation, and 1 at a different pulmonary vein. CONCLUSIONS: After focal ablation, atrial fibrillation recurred from other foci in the same pulmonary vein or other pulmonary veins. Therefore, three or four pulmonary veins should be isolated. However, atrial fibrillation recurred after pulmonary vein isolation due to the recovery of atrio-pulmonary vein conduction or non-pulmonary vein foci. Further development of new mapping and ablation systems to detect the foci and create a complete lesion at the pulmonary vein ostium may be necessary.     

Curative catheter ablation for atrial fibrillation

Optional statement With the recent advances in the understanding of the mechanisms of atrial fibrillation, radiofrequency catheter ablation has emerged as an effective therapeutic modality for patients with atrial fibrillation. Techniques for catheter ablation evolved from elimination of triggers that often originate within the pulmonary veins and initiate atrial fibrillation, to additional left atrial ablation using a variety of approaches to also eliminate the mechanisms that play a role in perpetuation of atrial fibrillation. With the current ablation strategies, atrial fibrillation can be eliminated in approximately 85% of patients with paroxysmal, and in approximately 70% of patients with chronic, atrial fibrillation with a low incidence of significant complications. In symptomatic patients with paroxysmal or chronic atrial fibrillation who have failed antiarrhythmic drug therapy, catheter ablation is an effective treatment strategy for maintenance of sinus rhythm.     

Bezold-Jarisch-Like Reflex During Radiofrequency Ablation of the Pulmonary Vein Tissues in Patients with Paroxysmal Focal Atrial Fibrillation

Pulmonary Vein Ablation-Induced Bradycardia. Introduction: Information is lacking about the occurrence of radiation-related proarrhythmic events during application of radiofrequency (RF) energy at (he pulmonary veins in patients with paroxysmal focal atrial fibrillation. The purpose of this study was to assess the theoretical risk of reflex bradycardia and hypotension response during RF ablation of these regions rich in endocardial nerve terminals.
Methods and Results: Among the 40 consecutive patients (29 men, 11 women; mean age 65 ± 12 years) with clinically documented frequent attacks of paroxysmal atrial fibrillation who underwent superior pulmonary vein ablation for left local atrial fibrillation, 6 patients (15%) developed bradycardia-hypotension syndrome during energy delivery. A single atrial fibrillation trigger focus in the left or right superior pulmonary vein was found in 3 and 1 patients, respectively. Two patients had two trigger foci originating from the orifice or proximal part of both superior pulmonary veins. After RF current was applied for a period of 14 ± 10 seconds, 2 patients developed functional rhythm and sinus bradycardia, another 2 patients had profound sinus bradycardia, I patient had two episodes of sudden onset of complete AV block with resultant 9.5-second a systole, and I patient showed profound sinus bradycardia, transient AV block, and an K-second asystole due to sinus arrest. Blood pressure fell when any substantial bradyarrhythmias occurred. All 6 patients were free of rhythm disturbances during The postablation follow-up period (mean 8 ± 2 months).
Conclusion: RF catheter ablation of the pulmonary vein tissues could evoke a variety of profound bradycardia-hypotension responses. The Bezold-Jarisch-like reflex might be the underlying mechanism.     

Initiation of atrial fibrillation by ectopic beats originating from the ostium of the inferior vena cava

Ectopic beats triggering atrial fibrillation may arise from atrial myocardial extensions in the pulmonary veins, superior vena cava, coronary sinus, and vein of Marshall. We report two patients with paroxysmal atrial fibrillation initiated by ectopic beats originating from the inferior vena cava. The foci responsible for the ectopic beats were located and ablated, resulting in elimination of atrial fibrillation. Ectopic beats originating from the os of the inferior vena cava can result in atrial fibrillation. This finding may explain the recurrence of atrial fibrillation in some patients after pulmonary vein isolation.     

Spontaneous Transition from Atrial Fibrillation to Typical Atrial Flutter during Catheter Ablation of the Pulmonary Vein

A 71-year-old male patient was admitted for catheter ablation of the pulmonary veins to treat paroxysmal atrial fibrillation. Atrial fibrillation originating from the left superior pulmonary vein was induced after a pause of atrial pacing under isoproterenol infusion and became sustained. Spontaneous transition from atrial fibrillation to typical atrial flutter was noted after complete isolation of the pulmonary vein focus from the left atrium. Subsequently linear ablation of the cavotricuspid isthmus was created with completely bi-directional isthmus conduction block. We hypothesized that ectopic pulmonary vein focus played an important role in the spontaneous conversion of atrial fibrillation to typical atrial flutter, and complete isolation of the pulmonary vein could stop the spontaneous transition between the two atrial tachyarrhythmias.     

Comparison of endocardial activation times at effective and ineffective ablation sites within the pulmonary veins

INTRODUCTION: Recent studies demonstrated that atrial arrhythmias may be generated within pulmonary veins. The purpose of this study was to compare the endocardial activation times at effective and ineffective ablation sites during radiofrequency catheter ablation of arrhythmias initiated or generated within pulmonary veins. METHODS AND RESULTS: Twenty-one of 28 patients without structural heart disease underwent successful ablation of 23 arrhythmogenic foci within a pulmonary vein. Electrograms were recorded at 75 pulmonary venous sites and categorized into three groups: 23 successful ablation sites; 28 unsuccessful target sites within an arrhythmogenic pulmonary vein; and 24 sites within nonarrhythmogenic pulmonary veins. The endocardial activation time of premature depolarizations arising at successful target sites was significantly earlier than at other sites. During premature depolarizations, an endocardial activation time of -75 msec or earlier had a sensitivity of 83% and a specificity of 79% for identification of a successful ablation site. Endocardial activation times earlier than -100 msec were recorded only at successful ablation sites, and endocardial activation times later than -30 msec were recorded only at sites within nonarrhythmogenic pulmonary veins. The presence of a split potential during sinus rhythm or premature depolarizations was not a specific indicator of a successful ablation site. CONCLUSION: The endocardial activation times of premature depolarizations that arise within pulmonary veins and initiate atrial tachycardia/fibrillation are useful in identifying successful ablation sites.     

Radiofrequency catheter ablation of atrial fibrillation initiated by spontaneous ectopic beats

Several reports have demonstrated that most paroxysmal atrial fibrillation is initiated by ectopic beats from a focal area, and radiofrequency catheter ablation can effectively cure atrial fibrillation. Although most of the ectopic beats originate from the orifices of the pulmonary veins or from the myocardial sleeves in the pulmonary veins, ectopic beats can also originate from superior vena cava, crista terminalis, coronary sinus, ligament of Marshall, or left atrial posterior free wall. Owing to the potential risk and complexity of catheter ablation, the ideal candidates should have frequent episodes and drug refractory paroxysmal atrial fibrillation.