Recovery Of Pulmonary Vein Conduction Research Articles

Electrophysiological characteristics of pulmonary vein conduction recovery after radiofrequency ablation of atrial fibrillation.

This study aimed to identify the specific site of pulmonary vein conduction recovery after radiofrequency ablation (RFA) of atrial fibrillation (AF) for improved outcomes and reduced recurrence. Patients who underwent RFA for AF at our institution were included. The ablation procedure was guided by the ablation index (AI) and left, and right atrial pressures were monitored before and after ablation. Additionally, the recovery time of the sinoatrial node under Burst 400/300 ms stimulation was examined. Among 60 repeat procedure patients, 48 had paroxysmal and 12 had persistent AF. The recovery sites were 36.6% in the left anterior superior, 35% in the right anterior superior, 20% in the left anterior inferior, 20% in the right anterior inferior, 13.3% in the right top, and 11.6% in the left top. Preoperative and postoperative left and right atrial pressures were significantly higher in the persistent AF group compared with the paroxysmal AF group (P < 0.01). Postoperative left atrial pressures were significantly elevated compared to the preoperative levels in both groups (P < 0.01). Sinoatrial node recovery time in the persistent AF group was significantly longer compared with the paroxysmal AF group (P < 0.01). Under the guidance of AI, the recurrence of atrial fibrillation after radiofrequency surgery and the recovery of pulmonary vein potential are mostly concentrated in the upper anterior, lower anterior, and upper left and right pulmonary veins. As the duration of atrial fibrillation prolongs, the left and right atrial pressure increases year by year, while the recovery time of the sinus node gradually prolongs.

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique: 9-year outcome

Abstract Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns after procedures performed with the first or second generation cryoballoon). Methods Two hundred and twenty patients (paroxysmal AF: 140 patients, persistent AF: 80 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (First generation: 110 patients (group A); second generation: 110 patients (group B)). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (three-dimensional mapping system) depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.6 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.2 re-conducting PVs, group B: 1.0 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 97 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1-3 reconnected PVs; group A1). In the remaining 13 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in nearly all patients (109/110) because there was only a minor reconnection of 1-2 PVs. All recovered PVs could be isolated sucessfully again. At 108-month follow-up, 69.1 % of all patients were free from an arrhythmia recurrence (152/220 patients; group A: 72/110 patients (65.5 %), group B: 80/110 patients (72.3 %)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon).

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique: 4-year follow-up

Abstract Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns ater procedures performed with the first or second generation cryoballoon). Methods One hundred and fifty patients (paroxysmal AF: 99 patients, persistent AF: 51 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (Arctic Front Balloon: 75 patients (group A); Arctic Front Advance: 75 patients (group B)). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (CARTO) depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.7 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.1 re-conducting PVs, group B: 1.3 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 65 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1–3 reconnected PVs; group A1). In the remaining 10 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in all patients because there was only a minor reconnection of 1–2 PVs. All recovered PVs could be isolated sucessfully again. At 48-month follow-up, 74.7% of all patients were free from an arrhythmia recurrence (112/150 patients; group A: 51/75 patients (68%), group B: 61/75 patients (81.3%)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon). Funding Acknowledgement Type of funding source: None

P1382Extended long-term follow-up of radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (first versus second generation cryoballoon)

Abstract Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns ater procedures performed with the first or second generation cryoballoon). Methods One hundred and twenty patients (paroxysmal AF: 78 patients, persistent AF: 42 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique. The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.8 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.1 re-conducting PVs, group B: 1.5 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 53 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1-3 reconnected PVs; group A1). In the remaining 7 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in all patients because there was only a minor reconnection of 1-2 PVs. All recovered PVs could be isolated sucessfully again. At 42-month follow-up, 78 % of all patients were free from an arrhythmia recurrence (94/120 patients; group A: 43/60 patients (71 %), group B: 51/60 patients (85 %)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon).

P445 Incidence of pulmonary vein conduction recovery after a 2-minute cryoballoon freeze for pulmonary vein isolation

P445 Incidence of pulmonary vein conduction recovery after a 2-minute cryoballoon freeze for pulmonary vein isolation

Early Pulmonary Vein Conduction Recovery after Catheter Ablation of Atrial Fibrillation.

Pulmonary vein electrical isolation (PVI) is an effective treatment for atrial fibrillation (AF). However, recurrence of pulmonary vein (PV) conduction after ablation may limit long-term success. Early identification and treatment of acute PV conduction recovery during initial ablation may have an impact on subsequent clinical results. To assess the prevalence of acute PV conduction recovery during the observation time after PV isolation for paroxysmal AF, and to evaluate the impact of re-isolation treatment on long-term clinical results. 76 patients with paroxysmal AF were randomized to 2 groups to undergo PVI. Group A (Study Group: 38 patients): 30 minutes of observation were given following PV isolation for detection of acute PV-reconnection, with re-ablation of reconnected PVs. Group B (Control Group: 38 patients). Ablation procedure was done either by conventional method or using 3D electro-anatomical mapping. Symptoms, ECG and Holter monitoring were used to evaluate the clinical effectiveness of ablation. Any episode of symptomatic or asymptomatic atrial tachyarrhythmia that lasted more than 30 seconds documented with ECG or Holter monitoring was considered a recurrence. There was no statistically significant difference in age, sex, AF history, previous AF ablation, structural heart diseases & antiarrhythmic drug history among both groups. In the study group, 14 patients (36.8%) showed no PV reconnection, while 24 patients (63.2%) showed acute PV reconnection within 30 minutes. The LSPV showed the highest rate of acute PV reconnection during the observation period (66.6% of patients showing PV reconnection). AF recurred in only 6 patients (15.8%) in the study group in comparison to 20 patients (52.6%) having AF recurrence post-ablation in the control group. Among 24 patients of the study group, who showed PV reconnection which was re-isolated, only 4 patients (16.7%) had AF recurrence on follow up. In patients who did not show PV reconnection (14 patients), only 2 patients (14.3%) had AF recurrence on follow up. Re-isolation of recovered PV conduction contributed to the improvement in the success rate of ablation for paroxysmal AF.

A clinical study on the electrophysiological characteristics of patients without recurrence after ablation of persistent atrial fibrillation

BackgroundThe electrophysiological characteristics of patients without recurrence after ablation of persistent atrial fibrillation (AF) have not been systematically determined. This study compared the electrophysiological characteristics in patients with and without recurrence of AF after persistent AF ablation. MethodsForty-five patients without recurrence of AF after persistent AF ablation were enrolled to assess electrophysiological characteristics including pulmonary vein (PV) reconnection, the mitral isthmus (MI) line and the roof line reconduction. Ninety-five patients with recurrence of AF after ablation were used as the control group. ResultsAmong patients without recurrence, recovery of PV conduction was observed in 37 of 45 (82.2%) patients: 3/45 (6.7%) reconnection in 4 veins, 7/45 (15.6%) in 3 veins, 11/45 (24.4%) in 2 veins, and 16/45 (35.6%) in 1 vein. No significant differences were seen in the proportion of patients with PV reconnection compared to patients with recurrence (p>0.05). Among patients without recurrence, the MI line reconduction was observed in 3/45 (6.7%) patients; the roof line conduction was observed in 5/45 (11.1%) patients. In comparison, patients with clinical recurrence of AF had recovery of the MI line conduction in 27/95 (28.4%) and recovery of the roof line conduction in 26/95 (27.4%). Significant differences were seen between these two groups (6.7% vs 28.4%, p=0.004; 11.1% vs 27.4%, p=0.031). ConclusionAlthough a high incidence of PV reconnection was similarly observed in patients with and without recurrence of AF, a lower incidence of lines reconduction was observed in patients without recurrence of AF.

Sites With Small Impedance Decrease During Catheter Ablation for Atrial Fibrillation Are Associated With Recovery of Pulmonary Vein Conduction.

To correlate impedance decrease during atrial fibrillation (AF) ablation with lesion durability and PV conduction recovery demonstrated during redo procedures. Markers of successful ablation beyond acute conduction block are needed to improve durability of pulmonary vein (PV) isolation (PVI). Local impedance decrease resulting from ablation is a real-time marker of tissue heating and is correlated with lesion creation. Impedance changes associated with point-by-point radiofrequency ablation in the PV antra were recorded during 167 consecutive first-time AF ablations. During clinically indicated redo procedures, sites of recovered PV conduction were identified, and were correlated with the impedance change achieved during ablation at these locations during the initial procedure. Redo procedures were performed in 28 patients, in whom 19 sites of recovered PV conduction were documented. Most sites of PV reconnection (58%) occurred along the posterior PV antra. Ablation resulting in impedance decrease <10 ohms during the initial procedure was present in 89% (17/19) of sites with conduction recovery. Regions with adjacent ablation resulting in impedance decrease <10 ohms were associated with a higher rate of conduction recovery (37% vs. 1.5%, P < 0.001). Likewise, patients with PV conduction recovery demonstrated during redo procedure (Group 1) had larger regions where ablation resulted in <10 ohm impedance decrease than patients without PV conduction recovery (Group 2) (21.9 ± 15.5 mm vs. 11.5 ± 2.1 mm, P < 0.01). Recovered PV conduction occurs predominantly in regions where adjacent ablation applications result in impedance decreases <10 ohms. Impedance-guided ablation strategies may improve durability of PVI.

The Timing and Frequency of PulmonaryVeins Unexcitability Relative to Completion of a WideArea Circumferential Ablation Line for Pulmonary Vein Isolation.

This study sought to assess loss of pulmonary vein (PV) excitability to pacing relative to the development of entrance block and the anatomic completion of the circumferential radiofrequency ablation (RFA)line. During encircling RFA for PV isolation (PVI), entrance block develops before anatomic completion of encirclement (early) in some patients. We hypothesized that early entrance block may be associated with loss of PV excitability to pacing. In 30 patients undergoing PV isolation (age 61 ± 10 years, 21 men), excitability to pacing was assessed atpredefined PV sites when entrance block developed and after completion of the RFA line. Of 60 PV pairs, 37 developed entrance block early, with a gap≥10 mm in the RFA line. In only 35% of PV pairs in this subgroup, both PV sleeves captured, and all of the capturing PV pairs showed exit block (no conduction from PVtoatrium) despite the presence of an excitable gap. In the remaining 23 PV pairs, entrance block did not occur untilencircling RFA was anatomically complete. In 83% of these PV pairs, both sleeves captured with exit block (p<0.001compared with early block PVs). The majority of PV pairs develops entrance and exit block before complete anatomic encircling by RFAlesions. Early entrance block is frequently associated with loss of PV sleeve excitability, consistent with a spreading waveof injury or edema rather than a permanent conduction barrier. This may help to explain the significant rate of PV conduction recovery associated with the acute endpoints of entrance and exit block.

Incidence of pulmonary vein conduction recovery in patients without clinical recurrence after ablation of paroxysmal atrial fibrillation: Mechanistic implications

Pulmonary vein (PV) isolation has become the mainstay acute procedural end point for paroxysmal atrial fibrillation (AF) ablation. To examine the incidence of conduction recovery in the PVs in patients without clinical recurrence of AF after paroxysmal AF ablation. From August 2008 to March 2011, 392 patients with drug-refractory PAF underwent catheter ablation in our center, a wide area circumferential ablation approach guided with a circular mapping catheter was performed with the intended endpoint of entrance block in all PVs. 276 (70.4%) of them were free from recurrence at one year follow-up, and 32 of them were enrolled to assess the incidence of PV reconnection. Forty-three patients with clinical recurrence after ablation were analyzed for comparison. The regions of gap were mapped and characterized in all of the reconnected PVs. Among patients without recurrence, recovery of PV conduction was observed in 29 of 32 (90.6%) patients: 10/32 (31.2%) reconnection in 4 veins, 7/32 (21.9%) in 3 veins, 10/32 (31.2%) in 2 veins, and 2/32 (6.2%) in 1 vein. No anatomic propensity was seen because reconnection was evenly distributed throughout all veins (left superior pulmonary vein 21, left inferior pulmonary vein 20, right superior pulmonary vein 19, and right inferior pulmonary vein 23). When compared to patients with recurrence, no significant differences were seen in the proportion of patients with reconnection (P = 1.0) or in left atrium-PV intervals (73.4 ± 43.3 ms vs 61.9 ± 31.8 ms; P > .05). A high incidence of PV reconnection was similarly observed in patients with and without recurrence of AF, suggesting that sustained PV isolation may not be required for freedom from clinical recurrence of AF.

How to Achieve Complete and Permanent Pulmonary Vein Isolation without Complications.

The efficacy and safety of catheter ablation for the management of atrial fibrillation (AF) has been improved in recent years. Radiofrequency (RF) catheter ablation for maintaining sinus rhythm is superior to the current antiarrhythmic drug therapy in selected patients. Pulmonary vein isolation (PVI) is the cornerstone of various catheter ablation strategies. It is well recognized that pulmonary vein (PV) antrum contributes to the AF initiation and/or perpetuation. Since PV stenosis is a complication of ablation within a PV, the ablation site for PVI has shifted to the junction between the left atrium and the PV rather than the ostium of the PV. However, PV reconnection after ablation is the major cause of recurrence of AF. The recovery of PV conduction could be caused by anatomical variations such as the failure to produce complete transmural lesion or gaps at the ablation line due to the transient electrophysiologic effects from the RF ablation. In this review, we discussed several factors to be considered for the achievement of the best PVI, including clinical aspects and technical aspects.

Unipolar Electrogram Morphology to Assess Lesion Formation During Catheter Ablation of Atrial Fibrillation

The past decade has seen a significant increase in catheter ablation procedures for atrial fibrillation (AF)1; however, data on the efficacy of pulmonary vein (PV) isolation (PVI) are soberingly modest, with single and multiple procedure success rates of 54% and 79% for paroxysmal AF, respectively, during long-term follow-up (≥3 years).2 The main mechanism of AF recurrence after catheter ablation is resumption of PV-left atrial (LA) conduction.3 The time-dependent inevitability of recovery of PV conduction has been consistently demonstrated in acute studies showing PV conduction in ≤93% of patients during an intraprocedural waiting period of 60 minutes after PVI.4 Furthermore, late recurrence of AF is associated with conduction recovery in ≥1 PV in >97% of patients who are having a redo procedure.2 Thus, durable PVI is critical if we are to make inroads toward enhancing procedural efficacy. Article see p 1095 Gaps in the ablation line5 and failure to produce transmural lesions6 are implicated in recovery of PV conduction. PVI can be achieved after partial completion of a circumferential ring of lesions around the PVs, irrespective of intervening gaps. This is thought to result from a combination of irreversible and reversible atrial injury.7 Reversible atrial injury may stem from incomplete lesion formation that causes temporary electric uncoupling but not cell death ≤3.5 mm away from the lesion boundary, dependent on tissue temperature and tissue geometry.8 With time, tissue at the boundary of the transmural lesion recovers normal conduction during the course of 1 to 4 weeks.8 Thus, lesion gaps that exhibit conduction block frequently go undetected during the index procedure, and block persists for up to several weeks or months thereafter until tissue injury heals. Conduction block may occur in tissue with normal conductivity despite a gap of ≤1.4 mm …

Histopathologic Characterization of Chronic Radiofrequency Ablation Lesions for Pulmonary Vein Isolation

This study describes the histopathologic and electrophysiological findings in patients with recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation who underwent a subsequent surgical maze procedure. The recovery of PV conduction is commonly responsible for recurrence of AF after catheter-based PV isolation. Twelve patients with recurrent AF after acutely successful catheter-based antral PV isolation underwent a surgical maze procedure. Full-thickness surgical biopsy specimens were obtained from the PV antrum in areas of visible endocardial scar. Before biopsy, intraoperative epicardial electrophysiological recordings were taken from each PV using a circular mapping catheter. Twenty-two PVs were biopsied from the 12 patients 8 ± 11 months after ablation. Eleven of the 22 specimens (50%) revealed transmural scar, and 11 (50%) showed viable myocardium with or without scar. Each biopsy specimen demonstrated evidence of injury, most commonly endocardial thickening (n = 21 [95%]) and fibrous scar (n = 18 [82%]). Seven of the 22 specimens (32%) showed conduction block at surgery. Transmural scar was more likely to be seen in the biopsy specimens from the PVs with conduction block than in specimens from the PVs showing reconnection. However, viable myocardium alone or mixed with scar was seen in 2 specimens from PVs with conduction block. PVs showing electrical reconnection after catheter-based antral ablation frequently reveal anatomic gaps or nontransmural lesions at the sites of catheter ablation. Nontransmural lesions are noted in some PVs with persistent conduction block, suggesting that lesion geometry may influence PV conduction. The histological findings show that nontransmural ablation can produce a dynamic cellular substrate with features of reversible injury. Delayed recovery from injury may explain late recurrences of AF after PV isolation.

Efficacy of Cut-and-Sew Box Isolation of the Posterior Left Atrium for Treatment of Atrial Fibrillation�Long-term Follow-up after a Modified Maze Procedure

Box isolation of the posterior left atrium is one surgical or catheter ablative approach for treating atrial fibrillation (AF). In such cases, incomplete transmurality or recovery of pulmonary vein conduction after the application of various ablative techniques is considered the main reason for the recurrence of postprocedural arrhythmia. The use of solely cut-and-sew box isolation does not have these disadvantages and therefore demonstrates maximum efficacy for this therapeutic approach. We treated 15 patients with both an indication for open heart surgery and AF (2 paroxysmal, 6 short persistent [<12 months], and 7 long persistent [>12 months] cases) with a solely cut-and-sew box lesion. These patients were then retrospectively followed up over the long term with respect to the end point of freedom of atrial tachyarrhythmias >30 seconds. The median follow-up duration was 42 months (range, 32-84 months). Five (63%) of 8 patients with preoperative paroxysmal or short persistent AF had no arrhythmia recurrence, whereas arrhythmia recurrence was documented in all 7 patients with preoperative long persistent AF. Despite reliable transmural isolation with cut-and-sew lesions, we observed long-term arrhythmia recurrence in patients who had preoperative paroxysmal or short persistent AF, suggesting that therapy approaches that are more complex than box isolation might be needed for selected patients to achieve long-term stable sinus rhythm, despite the initially paroxysmal or short persistent character of the arrhythmia. A high rate of recurrence in patients with severe structural heart disease and preoperative long persistent AF might indicate that, in general, isolation of the left posterior atrium alone is not an adequate therapeutic approach for these patients.

Exposing Gaps in Linear Radiofrequency Lesions

The termination of atrial fibrillation (AF) by radiofrequency ablation in the left atrium is undeniable evidence that the pathophysiology underlying AF can be ameliorated. The cornerstone of this therapy, pulmonary vein isolation, can be achieved acutely in virtually 100% patients.1,2 Recurrent AF is the bane of this procedure, however, and is most commonly attributed to recovery of pulmonary vein conduction through the ablation lines.2 Return of conduction across ablation lines to the mitral isthmus and the left atrial roof contribute to postablation arrhythmias as well. Intensive investigation of sophisticated ablation systems have failed to yield consistently durable ablation lines. Efforts to map and eliminate conductive gaps at the time of ablation have not resolved this problem. Gaps in linear ablation lines for AF ablation are a reality of current clinical practice. As a result, the single procedure success rate for AF ablation is constrained. It appears that a major advance in ablation and/or mapping technologies is needed to improve the state of catheter ablation for AF. Article see p 279 Despite the clinical problems they produce, gaps within ablation lines represent fascinating examples of myocardial electrophysiology. A brief review is relevant to placing new studies in perspective. The animal model of the myocardial gap was introduced almost 100 years ago by Garrey3 to study fibrillatory conduction patterns over an isthmus of myocardial tissue. With the advent of linear surgical and catheter-based ablation for AF, the model has been used extensively to reveal the complex conduction behavior associated with discontinuous linear lesions.4–10 Direct experimentation has benefited from computer modeling to provide deeper insights into gap conduction.11,12 A description of gap conduction invokes all 3 determinants of myocardial impulse propagation: (1) passive tissue electric properties, (2) excitable membrane properties, and (3) …

Visualization of lesion transmurality and depth of necrosis using an ablation catheter that incorporates ultrasound imaging: A small step or a major leap forward on the road to a more durable catheter ablation procedure for treatment of atrial fibrillation?

Percutaneous catheter ablation has revolutionized the care of patients with atrial fibrillation. Pulmonary vein isolation has become the cornerstone of most ablation procedures for the treatment of atrial fibrillation following the observation by Haissaguerre et al 1 Haissaguerre M. Jais P. Shah D.C. et al. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med. 1998; 339: 659-666 Google Scholar that pulmonary veins were a frequent source of ectopic beats initiating atrial fibrillation. Pulmonary vein isolation may be combined with linear ablation or ablation of other targets for treatment of persistent or longstanding persistent atrial fibrillation. Pulmonary vein electrical reconnection to the left atrium is not uncommon and may be the primary reason for procedure failure among patients with paroxysmal atrial fibrillation. 2 Callans D.J. Gerstenfeld E.P. Dixit S. et al. Efficacy of repeat pulmonary vein isolation procedures in patients with recurrent atrial fibrillation. J Cardiovasc Electrophysiol. 2004; 15: 1050-1055 Google Scholar , 3 Shah A.N. Mittal S. Sichrovsky T.C. et al. Long-term outcome following successful pulmonary vein isolation: pattern and prediction of very late recurrence. J Cardiovasc Electrophysiol. 2008; 19: 661-667 Google Scholar , 4 Cheema A. Dong J. Dalal D. et al. Incidence and time course of early recovery of pulmonary vein conduction after catheter ablation of atrial fibrillation. J Cardiovasc Electrophysiol. 2007; 18: 387-391 Google Scholar Pulmonary vein reconnections also have been demonstrated to be important triggers in patients with persistent atrial fibrillation undergoing repeat ablation. 5 Haissaguerre M. Jais P. Shah D.C. et al. Catheter ablation of chronic atrial fibrillation targeting the reinitiating triggers. J Cardiovasc Electrophysiol. 2000; 11: 2-10 Google Scholar Recovery of conduction across linear ablation lesions is also likely to play a role in procedure failure among patients with persistent atrial fibrillation. 6 Rostock T. O'Neill M.D. Sanders P. et al. Characterization of conduction recovery across left atrial linear lesions in patients with paroxysmal and persistent atrial fibrillation. J Cardiovasc Electrophysiol. 2006; 17: 1106-1111 Google Scholar With current technology, some tissue that is ablated recovers electrical activity. Any technology that could safely increase the probability that ablated tissue would remain ablated would be an important contribution. Real-time lesion assessment using a novel combined ultrasound and radiofrequency ablation catheterHeart RhythmVol. 8Issue 2PreviewAssessment of lesion size and transmurality is currently via indirect measures. Real-time image assessment may allow ablation parameters to be titrated to achieve transmurality and reduce recurrences due to incomplete lesions. Full-Text PDF

Early recovery of pulmonary vein conduction after cryoballoon ablation for paroxysmal atrial fibrillation: a prospective study

To assess the incidence of early pulmonary vein (PV) reconnection, characterize the anatomic features of the reconducting veins, and analyse the time course of their recovery in a series of consecutive patients with paroxysmal atrial fibrillation (AF) undergoing ablation with the Arctic Front Cryoballoon. We prospectively enrolled 26 patients (20 males; age 55.4 +/- 4.1) for circumferential PV cryoballoon isolation for highly symptomatic paroxysmal AF. Following isolation of all veins, we analysed PV potentials in each vein after 30 and 60 min with a circular mapping catheter. After successful electrical isolation of all 104 PV's, recurrence was observed only in three veins (2.8%) after 30 min. Two further cryoballoon applications in each of these veins lead to their isolation. These veins were still electrically disconnected at 60 min. No PV reconnection was observed in any of the other 101 veins (97.1%) at 30 and 60 min. Cryoballoon ablation of the PV's ostia is a very effective technique to achieve electrical isolation, with a very low rate of early reconnection.

Further Insight into the Technique and Outcomes of “Curative” Catheter Ablation of Atrial Fibrillation

During the past decade, catheter ablation of atrial fibrillation (AF) has emerged as an important treatment option for patients with symptomatic AF refractory to ≥1 antiarrhythmic agents. Electric isolation of the pulmonary vein musculature (PVI) has been identified as the primary end point for both catheter- and surgical-based AF ablation procedures.1 What is less clear is whether the addition of “linear lesions” or ablation of atrial sites demonstrating complex atrial electrograms improves outcome for patients with paroxysmal, persistent, or long-standing persistent AF.2,3 This issue remains an area of active discussion, debate, and investigation. Article see p 269 In this issue of Circulation: Arrhythmia and Electrophysiology , Gaita et al2 report the results of a prospective single-center randomized study of 204 patients who underwent catheter ablation for treatment of paroxysmal or persistent/permanent AF. Patients were stratified according to whether they had paroxysmal (n=125) or persistent/permanent (n=79) AF and were then randomized in a 2:1 fashion to undergo PVI alone or PVI combined with a “roof line” and a “left mitral line.” Follow-up visits that included an ECG, 24-hour Holter, and an echocardiogram were set up at 1, 3, 6, 12, 18, 24, and 30 months and then every year thereafter. If a patient experienced symptoms between follow-up visits, an event monitor was prescribed. A recurrence was defined as a symptomatic or asymptomatic episode of AF or atrial flutter lasting ≥30 seconds after a 2-month blanking period. Patients who developed a recurrence after the blanking period were offered a repeat ablation procedure. The outcome of ablation was evaluated at 12 months of follow-up and at completion of the study. Each patient was followed for a minimum of 3 years. Among the 125 patients with paroxysmal AF, the single-procedure success rate at 12 months was 46% with PVI alone versus …

Incidence and Time Course of Pulmonary Vein Conduction Recovery Following Electrical Isolation

Incidence and Time Course of Pulmonary Vein Conduction Recovery Following Electrical Isolation

Early identification and treatment of PV re-connections: role of observation time and impact on clinical results of atrial fibrillation ablation

Circumferential pulmonary vein isolation (CPVI) has been reported to account for 30% of atrial fibrillation (AF) recurrence after initial ablation, and pulmonary vein (PV) re-connection accounts for about 80% of AF recurrence. There is no information in the literature whether early identification and treatment of acute PV conduction recovery during initial ablation has an impact on subsequent clinical results. The objective is to investigate the prevalence of acute PV conduction recovery during the observation time after PV isolation for paroxysmal AF, and to evaluate the impact of re-isolation treatment on clinical results. Ninety cases with paroxysmal AF (51 males, mean age of 56.4 +/- 12.3 years) were randomized to 3 groups to undergo CPVI. In Group A, there was no observation time post-ablation. In Group B, there was 30 min of observation time post-ablation. In Group C, there was 60 min of observation time post-ablation. All PV re-conduction was re-isolated at the end of the observation time. ECG and Holter monitors were used to evaluate the clinical effectiveness of ablation. All cases underwent the procedure successfully. The mean procedural time in Group A was significantly shorter than in Group B and Group C, but there was no significant difference on fluoroscopic time and PV isolation time among the three groups. In Group B, PV re-conduction occurred in 8 cases (25%) at 30 min post-isolation, in 10 cases (31.2%) at 60 min post-isolation for left PVs, and in 6 cases (18.8%) at 30 min post-isolation for right PVs. In Group C, PV re-conduction for left PVs occurred in 9 cases (30%) at 30 min post-isolation and in 11 cases (36.7%) at 60 min post-isolation; for right PVs this occurred in 7 cases (23.3%) at 30 min post-isolation and in 8 cases (26.7%) at 60 min post-isolation. During a mean follow-up of 6.7 +/- 2.3 months, 17 cases (60.7%) in Group A, 27 cases (84.3%) in Group B, and 26 cases (86.7%) in Group C had no recurrence of atrial tachyarrhythmias, P = 0.04. The prevalence of acute PV conduction recovery was about 30% after PV isolation, which mostly occurred within 30 min after initial isolation. Re-isolation of recovered PV conduction contributed to the improvement in the success rate of ablation for paroxysmal AF.