Reduction of AF recurrence after pulmonary vein isolation by eliminating ATP-induced transient venous re-conduction

Background: Recent evidence has suggested that the transient re-conduction of the isolated pulmonary vein (PV) induced by the intravenous injection of adenosine (dormant PV conduction) might predict the incidence of subsequent venous reconnection after the procedure, which is the main cause of the atrial fibrillation (AF) recurrence after PV isolation (PVI). We tested the hypothesis that the elimination of these dormant PV conductions by additional radiofrequency (RF) applications can improve the efficacy of the PVI.
Methods and Results: One hundred forty-eight patients (124 males; mean age 53 ± 9 years) with drug-refractory AF underwent the PVI procedure. The standard PVI was performed in 94 patients (Group A), whereas the elimination of adenosine triphosphate (ATP)-induced dormant conduction using additional RF energy was performed in addition to the standard PVI in other 54 patients (Group B). Dormant conduction was observed in 56% of the patients (30/54) in Group B and 95% of these transient re-conductions were successfully eliminated by additional RF applications (mean: 1.5 ± 1.0 times). During the mean follow-up period of 20 months, recurrences of AF after the procedures were observed significantly less frequently in Group B (20%) than in Group A (40%) (P < 0.05).
Conclusion: The use of additional RF applications to eliminate transient PV reconnection induced by ATP injection led to a reduction of AF recurrence after PVI, most likely due to the minimization of the subsequent PV reconnection.     

Impact of adenosine-provoked acute dormant pulmonary vein conduction on recurrence of atrial fibrillation

Impact of ATP Reconduction on AF Recurrence. Introduction: Adenosine can be associated with acute recovery of conduction to the pulmonary veins (PVs) immediately after isolation. The objective of this study was to evaluate whether the response to adenosine predicts atrial fibrillation (AF) recurrence after a single ablation procedure in patients with paroxysmal AF. Methods and Results: A total of 109 consecutive patients (61 ± 10 years; 91 males) with drug‐refractory paroxysmal AF who underwent AF ablation were analyzed. After PV antrum isolation (PVAI), dormant PV conduction was evaluated by an administration of adenosine in all patients. No acute reconnections were provoked by the adenosine in 70 (64.2%) patients (Group‐1), but they were provoked in at least one side of the ipsilateral PVs in 39 (35.8%) patients (Group‐2). All adenosine‐provoked dormant conductions were successfully eliminated by additional ablation applications. By 12 months after the initial procedure, 72 (66.1%) patients were free of AF recurrences without any antiarrhythmic drugs. A Cox regression multivariate analysis of the variables including the adenosine‐provoked reconductions, age, gender, duration of AF, presence of hypertension or structural heart disease, left atrial size, left ventricular ejection fraction, and body mass index demonstrated that adenosine‐provoked reconductions were an independent predictor of AF recurrence after a single ablation procedure (hazard ratio: 1.387; 95% confidence interval: 1.018–1.889, P = 0.038). At the repeat session for recurrent AF, conduction recovery was observed similarly in both groups (P = 0.27). Conclusion: Even after the elimination of any adenosine‐provoked dormant PV conduction, the appearance of acute adenosine‐provoked reconduction after the PVAI was an independent predictor of AF recurrence after a single AF ablation procedure. (J Cardiovasc Electrophysiol, Vol. 23 p. 256‐260, March 2012.)     

Ablation of perimitral flutter following catheter ablation of atrial fibrillation: impact on outcomes from a randomized study (PROPOSE)

MVI Block vs Trigger Ablation in PMFL . Introduction: Patients with previous ablation for atrial fibrillation (AF) may experience recurrence of perimitral flutter (PMFL). These arrhythmias are usually triggered from sources that may also induce AF. This study aims at determining whether ablation of triggers or completing mitral valve isthmus (MVI) block prevents more arrhythmia recurrences. Methods and Results: Sixty‐five patients with recurrent PMFL after initial ablation of long standing persistent AF were included in this study. Thirty‐two patients were randomized to MVI ablation only (Group 1) and 33 were randomized to cardioversion and repeat pulmonary vein (PV) isolation plus ablation of non‐PV triggers (Group 2). MVI bidirectional block was achieved in all but 1 patient from Group 1. In Group 2, reconnection of 17 PVs was detected in 14 patients (42%). With isoproterenol challenge, 44 non‐PV trigger sites were identified in 28 patients (85%, 1.57 sites per patient). At 18‐month follow‐up, 27 patients (84%) from Group 1 had recurrent atrial tachyarrhythmias, of whom 15 remained on antiarrhythmic drug (AAD); however, 28 patients from Group 2 (85%, P < 0.0001 vs Group 1) were free from arrhythmia off AAD. The ablation strategy used in Group 2 was associated with a lower risk of recurrence (hazard ratio = 0.10, 95% CI 0.04–0.28, P < 0.001) and an improved arrhythmia‐free survival (log rank P < 0.0001). Conclusion: In patients presenting with PMFL after ablation for longstanding persistent AF, MVI block had limited impact on arrhythmia recurrence. On the other hand, elimination of all PV and non‐PV triggers achieved higher freedom from atrial arrhythmias at follow‐up. (J Cardiovasc Electrophysiol, Vol. 23, pp. 137‐144, February 2012)     

Cryoballoon Versus Radiofrequency for Pulmonary Vein Re‐Isolation After a Failed Initial Ablation Procedure in Patients with Paroxysmal Atrial Fibrillation

Cryoballoon versus Radiofrequency Ablation . Aim: Catheter ablation of paroxysmal atrial fibrillation (PAF) is associated with an important risk of early and late recurrence, necessitating repeat ablation procedures. The aim of this prospective randomized patient‐blind study was to compare the efficacy and safety of cryoballoon (Cryo) versus radiofrequency (RF) ablation of PAF after failed initial RF ablation procedure. Methods: Patients with a history of symptomatic PAF after a previous failed first RF ablation procedure were eligible for this study. Patients were randomized to Cryo or RF redo ablation. The primary endpoint of the study was recurrence of atrial tachyarrhythmia, including AF and left atrial flutter/tachycardia, after a second ablation procedure at 1 year of follow‐up. All patients were implanted with a cardiac monitor (Reveal XT, Medtronic) to continuously track the cardiac rhythm. Patients with an AF burden (AF%) ≤ 0.5% were considered AF‐free (Responders), while those with an AF% > 0.5% were classified as patients with AF recurrences (non‐Responders). Results: Eighty patients with AF recurrences after a first RF pulmonary vein isolation (PVI) were randomized to Cryo (N = 40) or to RF (N = 40). Electrical potentials were recorded in 77 mapped PVs (1.9 ± 0.8 per patient) in Cryo Group and 72 PVs (1.7 ± 0.8 per patient) in RF Group (P = 0.62), all of which were targeted. In Cryo group, 68 (88%) of the 77 PVs were re‐isolated using only Cryo technique; the remaining 9 PVs were re‐isolated using RF. In RF group, all 72 PVs were successfully re‐isolated (P = 0.003 vs Cryo). By intention‐to‐treat, 23 (58%) RF patients were AF‐free vs 17 (43%) Cryo patients on no antiarrhythmic drugs at 1 year (P = 0.06). Three patients had temporary phrenic nerve paralysis in the Cryo group; the RF group had no complications. Of the 29 patients who had only Cryo PVI without any RF ablation, 11 (38%) were AF‐free vs 20 (59%) of the 34 patients who had RF only (P = 0.021). Conclusion: When patients require a redo pulmonary vein isolation ablation procedure for recurrent PAF, RF appears to be the preferred energy source relative to Cryo. (J Cardiovasc Electrophysiol, Vol. 24, pp. 274‐279, March 2013)     

Acute and Chronic Effects of Cryoablation of the Pulmonary Veins in the Dog as a Potential Treatment for Focal Atrial Fibrillation

Background: Atrial fibrillation (AF) may be triggered by premature atrial depolarizations originating in the pulmonary veins (PV). Radiofrequency catheter ablation of PV foci may prevent recurrence of AF, but may cause PV stenosis. Therefore, a safer method for ablation of PV foci is needed. This study evaluated the acute and chronic effects of PV ablation using a cryocatheter ablation (CCA) system, which may be less likely to cause PV stenosis. Methods: CCA was performed by freezing for 5 minutes or more in one or more PVs in 10 anesthetized dogs. Pacing threshold and vessel diameter were measured before and after PV cryoablation. All dogs were restudied at 4.0 ± 1.64 months (range 2–7) in a manner identical to baseline. Results: CCA was performed in 27 PVs (range 1–4/dog), with a mean freeze time of 8.62 ± 5.42 minutes per vein (range 5.23–22.06). Mean temperature for all freezes was –65 ± 5.3°C. Mean PV diameter was 6.49 ± 1.73 vs 6.24 ± 1.83 mm (p = NS) and mean pacing threshold 1.32 ± 0.75 vs 9.36 ± 5.93 mA (p < .01), before vs. acutely after ablation. At followup, at the ablation sites PV diameter (7.02 ± 1.88 mm) was unchanged from baseline, whereas pacing threshold remained elevated (2.54 ± 1.44 mA, p < .05 vs baseline). There were no acute or long-term complications. Conclusions: (1) CCA of PVs produced a significant rise in acute and chronic pacing threshold indicating loss of atrial conductivity. (2) CCA of PVs did not cause PV stenosis or other complications. (3) The data suggest that CCA of PVs may be a safe and effective method for treating focal AF.     

Early Detection of Pulmonary Vein Reconnection After Isolation in Patients With Paroxysmal Atrial Fibrillation: A Comparison of ATP‐Induction and Reassessment at 30 Minutes Postisolation

Introduction: Catheter ablation for paroxysmal AF (PAF) is limited by an unacceptable recurrence rate, mainly due to pulmonary vein (PV) reconnection. Strategies to minimize reconnection include adenosine infusion and also a waiting period of 30 minutes after PV isolation. The aim of the present study was to assess whether these two strategies revealed the same conduction gap. Methods and Results: In total, 88 consecutive patients (54 males, mean age of 60 years) with drug refractory PAF underwent circumferential PV isolation (CPVI). After isolation of ipsilateral PVs, with entry and exit block checked using a circular mapping catheter, 20 mg ATP was injected during isoproterenol infusion to reveal dormant conduction gap(s). Unless the reconnection revealed by ATP persisted, PVs were further remapped with the circular mapping catheter at 30 minutes postisolation. Totally, PV reconnection was observed in 56 (64%) patients. 24.3% veins (80/329) were found reconnected. Reassessment at 30 minutes postablation was more efficient as compared to ATP induction (19.8% vs 14.6% for ATP). The agreement between these 2 methods is moderate (kappa value = 0.50). In veins that transiently reconnected after ATP administration and later observed at 30 minutes postablation, 94% (17 of 19) of them were found being reconnected with the same gap. Conclusion: Acute PV reconnection is common, occurring in 64% of patients, as detected by adenosine infusion and waiting time. Each shows a unique quality as compared to one another. The combined use of these 2 methods may reduce the AF recurrence rate after CPVI.     

Results of Short‐Term and Long‐Term Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation Using Duty‐Cycled Bipolar and Unipolar Radiofrequency Energy

PV Isolation Using Bipolar/Unipolar RF Energy . Background: Electrical disconnection of the pulmonary veins (PV) plays an important role in the ablation of paroxysmal atrial fibrillation (AF). Antral ablation using a conventional steerable ablation catheter often is technically challenging and time consuming. Methods: Eighty‐eight patients (mean age 58 ± 11 years) with symptomatic paroxysmal AF underwent ablation with a circular mapping/ablation decapolar catheter (PVAC). Ablation was performed in the antral region of the PVs with a power‐modulated bipolar/unipolar radiofrequency (RF) generator using 8–10 W delivered simultaneously through 2–10 electrodes, as selected by the operator. Seven‐day Holter monitor recordings were performed off antiarrhythmic drugs at 3‐, 6‐, and 12‐month follow‐up, and patients were requested to visit the hospital in the event of ongoing palpitations. All follow‐up patients were divided into 2 groups: Group 1 with a follow‐up of less than 1 year and group 2 patients completing a 1‐year follow‐up. Results: Overall, 338 of 339 targeted PVs (99%) were isolated with the PVAC with a mean of 24 ± 9 RF applications per patient, a mean total procedure time of 125 ± 28 minutes, and a mean fluoroscopy time of 21 ± 13 minutes. Freedom from AF off antiarrhythmic drugs was found in 82 and 79% of group 1 and group 2 patients, respectively. No procedure‐related complications were observed. Conclusion: PV isolation by duty‐cycled unipolar/bipolar RF ablation can be effectively and safely performed with a circular, decapolar catheter. Twelve‐month follow‐up data compare favorably with early postablation results, indicating stable effects over time. (J Cardiovasc Electrophysiol, Vol. 21, pp. 399–405, April 2010)     

Pressure‐Guided Cryoballoon Isolation of the Pulmonary Veins for the Treatment of Paroxysmal Atrial Fibrillation

Pressure‐Guided Cryoballoon Pulmonary Vein Isolation. Background: Pulmonary vein (PV) isolation using a balloon‐mounted cryoablation system is a new technology for the percutaneous treatment of atrial fibrillation (AF). Complete PV occlusion during balloon ablation has been shown to predict successful electrical isolation. The aim of this study was to correlate mechanical PV occlusion with changes in a pressure curve recorded at the distal tip of the cryoballoon catheter. Methods and Results: We analyzed 51 PVs in 12 patients (61 ± 6 years old) with paroxysmal AF. At first, PV occlusion via the cryoballoon was documented by changes in the pressure curve. Once the PV is occluded, the pressure curve registered in the vein converts from a left atrial pressure curve to a pulmonary artery pressure curve: the PV wedge curve. Occlusion was then confirmed by transesophageal echocardiography (TEE). Following 2 cryoablation applications, electrical PV isolation was assessed with a circumferential mapping catheter. Under the exclusive guidance of changes in the pressure curve at the tip of the cryoballoon, mechanical occlusion confirmed by TEE was achieved in 47 of 51 PVs (92%). Three PVs required further TEE guidance to achieve occlusion. All 50 occluded veins were electrically isolated after cryoablation. One right inferior vein, which could not be occluded with the balloon, displayed conduction post cryoablation and was isolated by focal ablation. Conclusions: Occlusion and electrical isolation of PVs during cryoballoon ablation can be predicted by the appearance of a PV wedge curve at the tip of the catheter. This new straightforward parameter may facilitate the procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 120‐125, February 2010)     

Pulmonary vein activation in atrial fibrillation and sinus rhythm.

AIMS: The purpose of this study was to determine the relationship between pulmonary vein (PV) electrical activation during atrial fibrillation (AF) and after cardioversion into sinus rhythm. METHODS AND RESULTS: Electrograms were recorded using a circular mapping catheter during AF and after cardioversion in 53 PVs from 41 patients. Two activation patterns were observed in AF. Group 1 had fixed, consistent, uniform activation sequences most (>70%) of the recording time. Group 2 had no fixed activation sequence. In Group 1, a constant single activation sequence pattern was seen in 22 PVs (Group 1a). The earliest PV activation sites were the same during AF and after cardioversion to sinus rhythm in 17 (77%) PVs from Group 1a. Fourteen of these 17 (82%) cases also had a common site of electrogram polarity reversal. In Group 2, a relationship between PV activation before and after cardioversion was not found. Segmental radio frequency (RF) ablation was performed during sinus rhythm after cardioversion. There was no difference in the number of atriovenous breakthroughs between the two groups (1.9+/-0.7 vs. 2.0+/-0.6 breakthroughs, P=NS). PV disconnection was achieved in all PVs with a mean RF duration of 13.5+/-4.5 min per vein in Group 1 and 14.0+/-4.9 min per vein in Group 2 (P=NS). CONCLUSION: A uniform PV electrogram pattern recorded during AF usually predicts the activation sequence and/or the polarity reversal sites during sinus rhythm. This pattern does not necessarily suggest a single atriovenous breakthrough point.     

Persistence of Pulmonary Vein Isolation After Robotic Remote‐Navigated Ablation for Atrial Fibrillation and its Relation to Clinical Outcome

Robotic Remote Ablation for AF . Aims: A robotic navigation system (RNS, Hansen?) has been developed as an alternative method of performing ablation for atrial fibrillation (AF). Despite the growing application of RNS‐guided pulmonary vein isolation (PVI), its consequences and mechanisms of subsequent AF recurrences are unknown. We investigated the acute procedural success and persistence of PVI over time after robotic PVI and its relation to clinical outcome. Methods and Results: Sixty‐four patients (60.7 ± 9.8 years, 53 male) with paroxysmal AF underwent robotic circumferential PVI with 3‐dimensional left atrial reconstruction (NavX?). A voluntary repeat invasive electrophysiological study was performed 3 months after ablation irrespective of clinical course. Robotic PVI was successful in all patients without complication (fluoroscopy time: 23.5 [12–34], procedure time: 180 [150–225] minutes). Fluoroscopy time demonstrated a gradual decline but was significantly reduced after the 30th patient following the introduction of additional navigation software (34 [29–45] vs 12 [9–17] minutes; P < 0.001). A repeat study at 3 months was performed in 63% of patients and revealed electrical conduction recovery in 43% of all PVs. Restudied patients without AF recurrence (n = 28) showed a significantly lower number of recovered PVs (1 (0–2) vs 2 (2–3); P = 0.006) and a longer LA‐PV conduction delay than patients with AF recurrences (n = 12). Persistent block of all PVs was associated with freedom from AF in all patients. At 3 months, 67% of patients were free of AF, while reablation of recovered PVs led to an overall freedom from AF in 81% of patients after 1 year. Conclusion: Robotic PVI for PAF is safe, effective, and requires limited fluoroscopy while yielding comparable success rates to conventional ablation approaches with PV reconduction as a common phenomenon associated with AF recurrences. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1079‐1084)     

A Prospective,Randomized Comparison of Modified Pulmonary Vein Isolation Versus Conventional Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation

Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012)     

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.     

Clinical implications of reconnection between the left atrium and isolated pulmonary veins provoked by adenosine triphosphate after extensive encircling pulmonary vein isolation

Introduction: Dormant pulmonary vein (PV) conduction can be provoked by adenosine triphosphate (ATP) after extensive encircling pulmonary vein isolation (EEPVI). However, the clinical implication of reconnection between the left atrium (LA) and isolated PVs provoked by ATP (ATP-reconnection) remains unknown.
Methods and Results: We studied the clinical consequences of ATP-reconnection during intravenous isoproterenol infusion (ISP-infusion). EEPVI severs conduction between the LA and ipsilateral PVs at their junction. Radiofrequency energy is applied at a distance from the PV ostia guided by double Lasso catheters placed within the ipsilateral superior and inferior PVs. This study comprised 82 patients (67 men, 56 ± 9 years old) with atrial fibrillation (AF) who underwent injection of ATP during ISP infusion after successful EEPVI (ATP(+) group). We compared clinical characteristics of 170 patients who underwent earlier EEPVI prior to our use of ATP injection after successful EEPVI (ATP(N/D) group) with those of ATP(+) group patients who underwent one session of EEPVI. ATP-reconnection occurred in 34 (41%) of 82 ATP(+) group patients. Additional radiofrequency applications were performed to eliminate ATP-reconnection in all ipsilateral PVs. Continuous ATP-reconnection of more than 20 seconds duration occurred in six (7.3%) of 82 patients. A total of 102 (60%) of 170 patients in the ATP(N/D) group had no recurrence of AF, whereas 60 (73%) of 82 ATP(+) group patients who underwent only one EEPVI session have had no recurrence of AF in a 6.1 ± 3.3-month follow-up period (P = 0.04).
Conclusion: Radiofrequency application for provoked ATP-reconnection may reduce clinical AF recurrence.     

Triggering Pulmonary Veins: A Paradoxical Predictor for Atrial Fibrillation Recurrence After PV Isolation

Triggering Pulmonary Veins and Recurrence After Ablation . Purpose: To identify procedural parameters predicting recurrence of atrial fibrillation (AF) after a first circumferential pulmonary vein isolation (CPVI). Methods: One hundred seventy‐one patients undergoing CARTO‐guided CPVI for recurrent AF with a left atrial (LA) diameter <45 mm were studied. Follow‐up (symptoms and 7‐day Holter) was performed at 1 and 3 months and every 3 months thereafter. Clinical and procedural characteristics between successful patients and patients undergoing repeat ablation were compared. In addition, procedural parameters of the first procedure were compared with parameters during repeat ablation. Results: After first CPVI, 80% of patients were free of AF without antiarrhythmic drugs after a follow‐up (FU) of 28 ± 11 months (N = 136). Thirty‐five patients (20%) had recurrence of AF of which 25 underwent repeat ablation (N = 25). Clinical characteristics did not differ between the successful and repeat group. A triggering vein during the index procedure was significantly more observed in the repeat group (56% vs 11%, P < 0.001). At repeat ablation, 2.6 ± 1.2 veins per patient were reconnected. Whereas there was no preferential reconnecting PV, all PVs triggering at index were reconnected (100%). Conclusions: (1) In patients with symptomatic recurrent AF, the presence of a triggering pulmonary vein during ablation is a paradoxical predictor for AF recurrence after PV isolation. (2) The consistent finding of reconnection of the triggering PV at repeat ablation, suggests that, in these patients, the triggering PV is the culprit vein and that reconnection invariably results in clinical AF recurrence. (3) The present study advocates a strategy of even more stringent PV isolation in case of a triggering PV. (J Cardiovasc Electrophysiol, Vol. 21, pp. 381–388, April 2010)     

Pulmonary Vein Contraction Before and After Radiofrequency Ablation for Atrial Fibrillation

Pulmonary Vein Contraction After Ablation. Introduction: Cardiovascular magnetic resonance imaging (cMRI) may provide a noninvasive method to test for pulmonary vein (PV) isolation after ablation for atrial fibrillation (AF) by detecting changes in PV contraction. Methods: PV contraction (the maximal percentage change in PV cross‐sectional area [CSA] during the cardiac cycle) measured 1 month before and 2 months after PV isolation was compared in 63 PVs from 16 patients with medically refractory AF. Repeat cMRI imaging and invasive catheter mapping was performed prior to repeat PV ablation in 50 PVs from 14 additional patients with recurrent AF. Contraction in PVs with sustained isolation after the initial ablation was compared to contraction in PVs with electrical reconnection to adjacent atrium. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff PV contraction value for prediction of PV‐atrial reconnection after ablation. The cutoff value was then prospectively tested in 40 PVs from 12 additional patients. Results: PV contraction decreased after AF ablation (22.4 ± 10% variation in CSA before ablation vs 10.1 ± 8% variation in CSA after ablation, P < 0.00001). PVs with sustained isolation on invasive mapping contracted less than PVs with electrical reconnection to adjacent atrium (13.7 ± 10.6% vs 21.4 ± 9.3%, P = 0.021). PV contraction produced a c‐index of 0.74 for prediction of PV‐atrial reconnection after ablation and >17% variation in PV CSA predicted reconnection with a sensitivity of 84.6% and specificity of 66.7%. Conclusion: PV contraction is reduced by ablation. PV contraction measurement may provide a noninvasive method to test for PV isolation after ablation procedures. (J Cardiovasc Electrophysiol, Vol. 22, pp. 169‐174, February 2011)     

Pulmonary Vein Stenosis After Atrial Fibrillation Ablation: Insights From the ADVICE Trial

BackgroundPulmonary vein (PV) stenosis is a complication of atrial fibrillation (AF) ablation. The incidence of PV stenosis after routine post-ablation imaging remains unclear and is limited to single-centre studies. Our objective was to determine the incidence and predictors of PV stenosis following circumferential radiofrequency ablation in the multicentre Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) trial.MethodsPatients with symptomatic AF underwent circumferential radiofrequency ablation in one of 13 trial centres. Computed tomographic (CTA) or magnetic resonance (MRA) angiography was performed before ablation and 90 days after ablation. Two blinded reviewers measured PV diameters and areas. PVs with stenosis were classified as severe (> 70%), moderate (50%-70%), or mild (< 50%). Predictors of PV stenosis were identified by means of multivariable logistic regression.ResultsA total of 197 patients (median age 59.5 years, 29.4% women) were included in this substudy. PV stenosis was identified in 41 patients (20.8%) and 47 (8.2%) of 573 ablated PVs. PV stenosis was classified as mild in 42 PVs (7.3%) and moderate in 5 PVs (0.9%). No PVs had severe stenosis. Both cross-sectional area and diameter yielded similar classifications for severity of PV stenosis. Diabetes was associated with a statistically significant increased risk of PV stenosis (OR 4.91, 95% CI 1.45-16.66).ConclusionsIn the first systematic multicentre evaluation of post-ablation PV stenosis, no patient acquired severe PV stenosis. Although the results are encouraging for the safety of AF ablation, 20.8% of patients had mild or moderate PV stenosis, in which the long-term effects are unknown.     

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

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

Pulmonary vein isolation as an end point for left atrial circumferential ablation of atrial fibrillation.

OBJECTIVES: We sought to determine whether elimination of pulmonary vein (PV) arrhythmogenicity is necessary for the efficacy of left atrial circumferential ablation (LACA) for atrial fibrillation (AF). BACKGROUND: The PVs often provide triggers or drivers of AF. It has been shown that LACA is more effective than PV isolation in eliminating paroxysmal AF. However, it is not clear whether complete PV isolation is necessary for the efficacy of LACA. METHODS: In 60 consecutive patients with paroxysmal (n = 39) or chronic (n = 21) AF (mean age 53 +/- 12 years), LACA to encircle the left- and right-sided PVs, with additional lines in the posterior left atrium and along the mitral isthmus, was performed under the guidance of an electroanatomic navigation system. The PVs were mapped with a decapolar ring catheter before and after LACA. If PV isolation was incomplete, no attempts at complete isolation were made. RESULTS: After LACA, there was incomplete electrical isolation of one or more PVs in 48 (80%) of the 60 patients. The prevalence of PV tachycardias was 82% before and 8% after LACA (p < 0.001). At 11 +/- 1 months of follow-up, 10 (83%) of the 12 patients with complete and 39 (81%) of 48 patients with incomplete PV isolation were free from recurrent AF without antiarrhythmic drug therapy (p = 1.0). A successful outcome was not related to the number of completely isolated PVs per patient (p = 0.6). CONCLUSIONS: Left atrial circumferential ablation modifies the arrhythmogenic substrate within the PVs. Complete electrical isolation of the PVs is not a requirement for a successful outcome after LACA.     

Long‐Term Outcome Following Successful Catheter Ablation of Atrial Tachycardia Originating From the Pulmonary Veins: Absence of Late Atrial Fibrillation

Atrial Fibrillation and Pulmonary Vein Tachycardia . Objectives: This study aimed to characterize the long‐term outcome and incidence of atrial fibrillation (AF) in patients following catheter ablation of focal atrial tachycardia (AT) from the pulmonary veins (PV). Background: Although both AT and AF may originate from ectopic foci within PVs, it is unknown whether PV AT patients subsequently develop AF. Methods: Twenty‐eight patients with 29 PV ATs (14%) from a consecutive series of 194 patients who underwent RFA for focal AT were included. Patients with concomitant AF prior to the index procedure were excluded. Results: The minimum follow‐up duration was 4 years; mean age 38 ± 18 years with symptoms for 6.5 ± 10 years, having tried 1.5 ± 0.9 antiarrhythmic drugs. The distribution of foci was: left superior 12 (41%), right superior 10 (34%), left inferior 5 (17%), and right inferior 2 (7%). The focus was ostial in 93% and 2–4 cm distally within the vein in 7%. Mean tachycardia cycle length was 364 ± 90 ms. Focal ablation was performed in 25 of 28 patients. There were 6 recurrences with 5 from the original site. Twenty‐six patients were available for long‐term clinical follow‐up. At a mean of 7.2 ± 2.1 years, 25 of 26 (96%) were free from recurrence off antiarrhythmic drugs. No patients developed AF. Conclusions: Focal ablation for tachycardia originating from the PVs is associated with long‐term freedom from both AT and AF. Therefore, although PV AT and PV AF share a common anatomic distribution, PV AT is a distinct clinical entity successfully treated with focal RFA and not associated with AF in the long term. (J Cardiovasc Electrophysiol, Vol. pp. 747‐750, July 2010)     

Comparison of ThermoCool® Surround Flow Catheter Versus ThermoCool® Catheter in Achieving Persistent Electrical Isolation of Pulmonary Veins: A Pilot Study

Persistent Electrical Isolation of Pulmonary Veins . Introduction: Aim of this study was to compare efficacy and safety of the new ThermoCool Surround Flow® catheter (SFc) versus the ThermoCool® (TCc) in achieving persistent circumferential electrical isolation of the pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (AF). Methods and Results: This multicenter, randomized, controlled study enrolled patients suffering from paroxysmal AF. Randomization was run in a one‐to‐one fashion between radiofrequency ablation by TCc or SFc. Aim of PVs ablation was documentation of electrical isolation with exit/entrance block recorded on a circular catheter. Among the 106 enrolled patients, 52 (49.0%) were randomized to TCc and 54 (51.0%) to SFc. Total volume of infused saline solution during the procedure was lower in the SFc than in TCc group (752.7 ± 268.6 mL vs 1,165.9 ± 436.2 mL, P < 0.0001). Number of identified and isolated PVs was similar in the 2 groups. Number of PVs remaining isolated 30 minutes after ablation was higher in the SFc than in TCc group (95.2% vs 90.5%, P < 0.03), mainly driven by acute ablation result in the left PVs (96.1% vs 89.7%, P < 0.04). Complications were seldom and observed only in the TCc group (0% vs 3.84%, P < 0.03). At 6‐month follow‐up SFc patients reported a trend toward less AF recurrences compared to those in the TCc group (22.9% vs 27.0%, P = 0.69). Conclusion: PV isolation by SFc lowered the rate of left PV early reconnections and reduced the volume of infused saline solution while maintaining the safety profile of AF ablation. (J Cardiovasc Electrophysiol, Vol. 24, pp. 269‐273, March 2013)