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.     

Anatomy of the pulmonary veins in patients with atrial fibrillation and effects of segmental ostial ablation analyzed by computed tomography

INTRODUCTION: The anatomic arrangement of pulmonary veins (PVs) is variable. No prior studies have quantitatively analyzed the effects of segmental ostial ablation on the PVs. The aim of this study was to determine the effect of segmental ostial radiofrequency ablation on PV anatomy in patients with atrial fibrillation (AF). METHODS AND RESULTS: Three-dimensional models of the PVs were constructed from computed tomographic (CT) scans in 58 patients with AF undergoing segmental ostial ablation to isolate the PVs and in 10 control subjects without a history of AF. CT scans were repeated approximately 4 months later. PV and left atrial dimensions were measured with digital calipers. Four separate PV ostia were present in 47 subjects; 3 ostia were present in 2 subjects; and 5 ostia were present in 9 subjects. The superior PVs had a larger ostium than the inferior PVs. Patients with AF had a larger left atrial area between the PV ostia and larger ostial diameters than the controls. Segmental ostial ablation resulted in a 1.5 +/- 3.2 mm narrowing of the ostial diameter. A 28% to 61% focal stenosis was present 7.6 +/- 2.2 mm from the ostium in 3% of 128 isolated PVs. There were no instances of symptomatic PV stenosis during a mean follow-up of 245 +/- 105 days. CONCLUSION: CT of the PVs allows identification of anatomic variants prior to catheter ablation procedures. Segmental ostial ablation results in a significant but small reduction in ostial diameter. Focal stenosis occurs infrequently and is attributable to delivery of radiofrequency energy within the PV.     

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.     

Incidence and predictors of very late recurrence of atrial fibrillation after ablation

Introduction: Radiofrequency catheter ablation can effectively treat patients with refractory atrial fibrillation (AF). Very late AF recurrence (≥12 months post-ablation) is uncommon and may represent a unique patient cohort.
Methods and Results: A nested case-control study was performed in the cohort who underwent AF ablation at the University of Pennsylvania to characterize patients who develop very late AF recurrence after ablation. The procedure consisted of isolation of pulmonary veins (PVs) demonstrating triggers and elimination of non-PV triggers initiating AF. Twenty-seven (7.9%) patients with very late recurrence were compared to 219 patients without recurrence and ≥12 months of follow-up. The mean age was 54.6 ± 11.3 years and 79% were men. Very late recurrence patients more likely weighed >200 lbs (70% vs 55%, P = 0.01); during initial ablation had fewer PVs isolated (2.8 ± 1.1 vs 3.3 ± 1.0, P = 0.03); and were less likely to have right inferior PV isolation (37% vs 61%, P = 0.02), less likely to have isolation of all PVs (30% vs 56%, P = 0.01), and more likely to have non-PV triggers (30% vs 11% OR 3.4(95% CI, 1.3–8.7), P = 0.01). PV reconnectivity and new triggers were found in the majority of patients with very late recurrence of AF who underwent repeat ablation.
Conclusion: Very late recurrence of AF more likely occurred in patients >200 lbs who demonstrated non-PV triggers and did not undergo right inferior PV isolation. The majority of patients undergoing repeat ablation for very late recurrence demonstrated PV reconnectivity and new non-PV and PV triggers not observed during the initial ablation.     

Transesophageal echocardiographic follow-up of pulmonary veins in patients undergoing ostial radiofrequency catheter ablation for atrial fibrillation.

BACKGROUND: Ostial radiofrequency catheter ablation (RFCA) of pulmonary veins (PVs) is a promising invasive approach for the non-pharmacologic treatment of atrial fibrillation, but PV stenosis has been reported as a possible complication of this intervention. The aim of this study was to assess PV anatomy and stenosis (i.e. number and progression) by means of transesophageal echocardiography (TEE) during the follow-up of patients undergoing RFCA. METHODS: Twenty-three consecutive patients with refractory and highly symptomatic atrial fibrillation underwent ostial radiofrequency isolation of arrhythmogenic triggers/foci, localized into the PVs, by an electroanatomic approach (CARTO system) or circular mapping with a multipolar catheter (LASSO) placed under radioscopic guidance. All patients were investigated using TEE and magnetic resonance angiography before radiofrequency application to evaluate PV anatomy. TEE examination was repeated after 2 months of follow-up and, in the presence of a stenosis, 1 year later. RESULTS: TEE allowed to identify 100% of the left and right superior PVs, 96% of right inferior PVs, and 74% of the left inferior PVs. Anatomic variants were detected at TEE in 33% of patients against 37% at magnetic resonance angiography (95% of concordance). After ostial RFCA, TEE disclosed a significant reduction in the mean diameters of the left superior PV (14.1 +/- 3.2 vs 12.0 +/- 2.7 mm, p < 0.01), left inferior PV (11.2 +/- 2.3 vs 9.8 +/- 2.2 mm, p = 0.05) and right superior PV (14.2 +/- 2.6 vs 12.9 +/- 2.7 mm, p < 0.05), and an increase in the mean peak velocities of the left superior PV (69.8 +/- 14.8 vs 91 +/- 42.4 cm/s, p < 0.05) and left inferior PV (59.2 +/- 18.1 vs 79.3 +/- 40.5 cm/s, p < 0.05). From a total of 88 PVs treated, 7 (7.9%) showed a higher significant stenosis in patients treated using the LASSO than the CARTO system (31.3 vs 2.8% respectively, p < 0.01). After 1-year follow-up there was no progression of PV stenosis. CONCLUSIONS: TEE was successful to evaluate PV anatomy and stenosis of patients undergoing ostial RFCA for atrial fibrillation. This complication is not rare and seems to be strictly related to the method of ablation, in particular when circular mapping and disconnection of triggers/foci was carried out by only a circular multipolar catheter without an electroanatomic approach.     

Intracardiac Doppler echocardiographic quantification of pulmonary vein flow velocity: an effective technique for monitoring pulmonary vein ostia narrowing during focal atrial fibrillation ablation

INTRODUCTION: Ablation at the pulmonary vein (PV) ostium to isolate triggers for atrial fibrillation (AF) may induce PV narrowing. The AcuNav ultrasound catheter can image PV flow and quantify peak velocity and may be useful in assessing the degree of narrowing of PV ostia. METHODS AND RESULTS: In 93 patients with AF undergoing PV ostial ablation (up to 40 W, 52 degrees C, 90 sec), the ultrasound catheter was placed in the right atrium and PV peak flow velocities were measured during systole and diastole before and after ablation. Ostial PV electrical isolation was achieved in 216 of the 219 targeted PVs. The ultrasound catheter provided flow imaging of all PVs. The ostial peak flow velocities measured 56 +/- 12 cm/sec before ablation and increased to 101 +/- 22 cm/sec after ablation (P < 0.001). Peak velocity >100 cm/sec was detected in 103 (47%) of 219 and > or = 158 cm/sec (estimated pressure gradient 10 mmHg) with turbulent flow features, in 7 (3.2%) of 219 PVs. The highest velocity detected in one PV was 211 cm/sec (17.7 mmHg). Follow-up ultrasound catheter measurements were obtained in 13 patients (30 previously ablated PVs) during repeat ablations. The ostial peak velocity had decreased by 22 +/- 14 cm/sec and in 25 (83%) of 30 PVs was within the baseline range (<100 cm/sec) at a mean follow-up of 4.9 +/- 2.2 months. Follow-up magnetic resonance imaging (MRI) or contrast-enhanced CT was obtained at 7.0 +/- 3.8 months in seven patients with PV velocity > 158 cm/sec after initial ablation. No significant stenosis (<30%) was identified, and no patient suffered clinical symptoms (follow-up 6-18 months) related to the described acute changes in PV flow after an initial ablation procedure. Of 13 patients with repeat ablation, two had PV velocities >100 cm/sec before repeat ablation, and three PVs in two patients had flow velocity >158 cm/sec after repeat ablation. One of these patients developed symptoms of exertional dyspnea; MRI at 4 months showed 50% to 60% ostial narrowing. CONCLUSION: Ostial ablation for PV isolation may induce a mild-to-moderate increase in PV flow velocity, which can be identified using an ultrasound catheter with Doppler color flow imaging. Increases in PV flow velocity (<158 cm/sec) after a primary ablation procedure appear to be well tolerated, and a return toward baseline flow characteristics should be anticipated by 3 months. A more cautious approach may be required for patients undergoing repeat PV isolation.     

Catheter ablation of focal triggers and drivers of atrial fibrillation

It has been demonstrated that most paroxysmal atrial fibrillation (AF) is triggered by ectopic beats originating from the pulmonary veins (PVs). It has been recently reported that some AF episodes are maintained by focal drivers and AF substrates in the PVs and atrium. Left atrial ablation combined with PV isolation targeting AF triggers and drivers may be effective for eliminating atrial arrhythmias. However, multiple AF drivers in the PVs and atrium and acute conduction recovery after the PV isolation may sometimes render that technique less reliable. In this article, we describe the current status of the catheter ablation of focal triggers and drivers of AF in the PVs and atrium, illustrating with case presentations.     

Mechanistic significance of intermittent pulmonary vein tachycardia in patients with atrial fibrillation

INTRODUCTION: The significance of intermittent tachycardia within a pulmonary vein (PV) during an episode of atrial fibrillation (AF) is unclear. The aim of this study was to determine the role that intermittent PV tachycardias play in AF. METHODS AND RESULTS: In 56 patients with AF, segmental ostial ablation guided by PV potentials was performed to isolate the PVs. The characteristics of intermittent PV tachycardias and the inducibility of AF before and after PV isolation were analyzed prospectively. During AF, a PV tachycardia (mean cycle length 130 +/- 30 msec) with exit block to the left atrium was present in 93% of left superior, 80% of left inferior, 73% of right superior, and 7% of right inferior PVs. The site of shortest cycle length during AF alternated between the PVs and left atrium 1 to 13 times per minute. Complete isolation was achieved in 168 (94%) of 178 targeted PVs. In 99% of PVs, tachycardia resolved upon isolation. AF was persistent before and after PV isolation in 100% and 27% of patients, respectively (P < 0.001). CONCLUSION: Intermittent bursts of tachycardia are observed within multiple PVs during persistent AF in a majority of patients. After PV isolation, PV tachycardias almost always resolve, and AF is less likely to be inducible or persistent. These observations suggest a dynamic interplay between the atria and PVs, with intermittent bursts of PV tachycardia being dependent on left atrial input and with the probability of persistent AF diminishing when PV tachycardias are eliminated by PV isolation.     

Effect of Heart Rate and Isoproterenol on Pulmonary Vein Flow Velocity Following Radiofrequency Ablation: A Doppler Color Flow Imaging Study

INTRODUCTION: Application of radiofrequency energy at pulmonary vein (PV) ostium during focal atrial fibrillation (AF) ablation procedures increases flow velocity due to PV narrowing. Factors unrelated to ablation that effect PV flow velocity have not been described. AIMS OF THE STUDY: The purpose of this study was to evaluate, using intracardiac echocardiography (ICE) imaging, the effect of isoproterenol (ISO) and heart rate (HR) on PV flow velocity Pre- and Post-ablation. METHODS AND RESULTS: In 31 patients with AF undergoing LA-PV ostial ablation involving at least one PV ostium, an ICE catheter was placed in the RA to image and detect PV flow. PV ostial peak velocity was assessed in sinus rhythm Pre-, Post-ablation, during and after ISO (up to 20 microg/min). To separate HR versus ISO effect, PV velocity was measured during atrial pacing (after HR returned to baseline) at pacing rate matching HR with ISO. PV ostial velocity was assessed with ISO and pacing in 30 non-ablated and 33 ablated PVs. Ostial velocities of non-ablated PVs during ISO infusion (117 +/- 42 cm/s) were greater ( p < 0.03) than those during atrial pacing (78 +/- 26 cm/s) at matched HR (116 +/- 20, range 92-150 bpm). Ostial PV flow velocities of ablated PVs increased from 59 +/- 17 (30-95) cm/s Pre- to 95 +/- 25 (58-136) cm/s Post-ablation. During ISO infusion PV flow velocities in ablated PVs (118 +/- 34 cm/s) were also greater ( p < 0.03) than those during atrial pacing (96 +/- 37 cm/s) at matched HR (116 +/- 14, range 92-130 bpm). Atrial pacing alone produced no significant difference in PV flow velocities measured Pre- or Postablation. CONCLUSION: ISO appears to increase ostial flow velocity of ablated and non-ablated PVs independent of HR effect. These effects are important to recognize when PV velocity is used as an index for interpreting the impact of PV ostial lesions on functionally significant PV narrowing.     

"Dormant" pulmonary vein conduction revealed by adenosine after ostial radiofrequency catheter ablation

INTRODUCTION: The endogenous nucleoside adenosine is an important intermediate in cellular metabolism, a regulator of function in many organ systems, and a pharmacologic agent with potent electrophysiologic effects. We studied the effects of adenosine on the activation of the pulmonary veins (PVs) after successful ostial isolation in patients with atrial fibrillation (AF). METHODS AND RESULTS: Twenty-nine patients (21 male; mean age 54 +/- 10 years) with refractory highly symptomatic persistent (n = 9) or paroxysmal (n = 20) AF were included in the study. PV isolation was performed using radiofrequency catheter ablation guided by a multipolar basket catheter (Constellation, Boston Scientific). After successful PV isolation, we studied the effects of intravenous adenosine (12-18 mg) on activation of the upper PVs. A total of 83 PVs were successfully isolated. After adenosine, PV activity was recorded in 10 (34%) of 29 left upper PVs studied and in 3 (13%) of 24 right upper PVs, coupled to atrial activity for 20 +/- 7 seconds (adenosine positive). In 8 (62%) of 13 cases, PV potentials were recorded in the distal electrodes of the basket catheter only. Dissociated PV rhythms (N = 8) present after PV isolation disappeared after adenosine for 18 +/- 7 seconds, even if reconduction was missing. In 14 patients (48%), a second EP study was performed for recurrence of AF. Adenosine-positive PVs had a nonsignificant higher rate of recovery of conduction than adenosine-negative veins (71% vs 35%, P = 0.095). CONCLUSION: Adenosine induces transient conduction in 25% of PVs following successful isolation. Further studies are necessary to determine the physiologic or pathophysiologic role of adenosine-induced reconduction in human hearts or other organ systems.     

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   

Predictors of success after selective pulmonary vein isolation of arrhythmogenic pulmonary veins for treatment of atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) ablation procedures typically involve isolation of all pulmonary veins (PVs) in addition to adjunctive linear lesions, yet the need for such an extensive ablation strategy in all patients is unclear. OBJECTIVES: The purpose of this study was to identify a subgroup of patients undergoing AF ablation with good clinical success after limited PV isolation. METHODS: Patients (N = 450) underwent trigger-guided segmental isolation of only arrhythmogenic PVs. We compared clinical characteristics of patients who required isolation of only one or two PVs to those in whom AF ablation required isolating > or = 3 PVs. RESULTS: For the group of patients undergoing isolation of < or = 2 PVs, AF freedom without antiarrhythmic drug use was achieved in 56 (58%) of 97 patients, and AF control was achieved in 66 (68%) of 97 patients after a single procedure. After additional procedures, 77 (79%) of 97 patients achieved complete AF freedom without antiarrhythmic drugs, and 82 (85%) of 97 patients achieved AF control. Younger age (odds ratio [OR] 1.05; confidence interval [CI] 1.01,1.09) and lack of persistent AF (OR 3.27; CI 1.0, 10.7) were each independent predictors of freedom from AF. In patients younger than 50 years with paroxysmal AF undergoing isolation of < or = 2 PVs (n = 44), AF freedom without antiarrhythmic drugs was achieved in 32 (73%) of 44 after a single ablation procedure. CONCLUSION: Targeted PV isolation has a good long-term (18-month) success rate in patients younger than 50 years with paroxysmal AF and < or = 2 PVs triggering AF.     

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.     

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

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

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.     

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.     

Characteristics and outcome in patients receiving multiple (more than two) catheter ablation procedures for paroxysmal atrial fibrillation

Background: The features of multiple catheter ablation procedures for paroxysmal atrial fibrillation (AF) are unknown. We aimed to investigate the electrophysiologic characteristics and the clinical outcomes in the patients with AF who received more than two ablation procedures.
Methods: The study consisted of 15 consecutive patients (age 48 ± 14 years, 10 males) who had undergone three to five (3.3 ± 0.6) catheter ablation procedures for recurrent paroxysmal AF.
Results: Ten patients had pulmonary vein (PV)-AF and one had AF originating from both PVs and the superior vena cava (SVC) in the first ablation procedure. All of them exhibited PV reconnection during the recurrent episodes. Four of the 15 patients had AF originating from non-PV foci (three from the SVC, one from the crista terminalis) in the first procedure, and two had AF recurrences due to recovered conduction from the SVC. In all patients with PV-AF recurrences, repeated PV isolation procedures could effectively eliminate the AF. The incidence of the need for additional LA linear ablation lesions was higher comparing between the first procedure and in the following ablation procedures (18% vs. 71%, P = 0.02). During a follow-up of 1.7 ± 1.1 years, 73% of the patients remained in sinus rhythm without any antiarrhythmic drugs after the final procedure.
Conclusions: Recovered PV connection was the major cause of the AF recurrences despite undergoing multiple catheter ablation procedures. It is advisable to inspect all PVs during the AF recurrence. Repeated PV isolation plus left atrial linear ablations could effectively eliminate the AF with satisfactory outcomes.     

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.     

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.     

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.