Multipolar mapping catheters with small electrodes provide more accurate and higher density maps, with a higher sensitivity to near-field signals. Agreement between PR and NAV is low.
P ulmonary vein isolation (PVI) is the cornerstone for catheter ablation procedures in patients with paroxysmal atrial fibrillation (AF).1 However, there is current concern about the durability of PVI because the PV reconnection rate has been recognized as substantial and clearly associated with the recurrence of paroxysmal AF episodes. 2 Editorial see p 1050 Clinical Perspective on p 1102PV reconnection may be related to the inability to create transmural and irreversible lesions around PV ostia. 3,4 In this regard, it has been demonstrated in a porcine model that complete elimination of the negative component of the unipolar atrial electrogram (EGM), while applying radiofrequency (RF) energy, was always associated with transmural lesions, whereas the persistence of such a negative component was constantly observed in case of nontransmural lesions. 5 In clinical practice, unipolar signal modification could be a suitable electrophysiological criterion that indicates when to halt each RF energy application while performing point-bypoint PVI (because a possible transmural lesion has been created) and when to continue its application (because the lesion deployed is presumed as not transmural).Therefore, we performed a prospective study to determine whether the unipolar signal modification may be useful or not as an end point for point-by-point RF application and find out whether it could improve the clinical results of paroxysmal AF ablations in humans by allowing more durable PVI achievement. We compared the results of the present study with those of a historical group of patients with paroxysmal AF who have undergone PVI following the standard ablative approach of our institution.© 2013 American Heart Association, Inc. Circ Arrhythm Electrophysiol Original ArticleBackground-In patients treated for paroxysmal atrial fibrillation, the pulmonary vein (PV) reconnection rate is substantial and may be related to the lack of transmurality achievement while performing PV isolation (PVI). It has been experimentally demonstrated that positive unipolar atrial electrogram completion, when applying radiofrequency energy, was associated with transmural lesions. In this regard, we seek to determine whether the unipolar signal modification may be an appropriate end point for point-by-point radiofrequency application and find out whether it could improve the paroxysmal atrial fibrillation ablation results in humans. Methods and Results-Fifty consecutive patients (61±8 years old, 41 men) with paroxysmal atrial fibrillation underwent PVI using Carto and Lasso. Each radiofrequency application lasted until development of a completely positive unipolar electrogram. Fifty patients (63±9 years old, 40 men), who previously underwent PVI following the standard approach of our institution, corresponded to the control group. All PVs were isolated in all patients of both groups. However, the procedural and ablation times were significantly lower in the unipolar group compared with those of the control group, whereas the PV reconnection rate...
E lectrophysiological pulmonary vein isolation (PVI) is the cornerstone of paroxysmal atrial fibrillation (AF) ablation.1 However, the incidence of AF recurrence remains high and mostly because of PV reconnection, 2,3 emphasizing the need for more understanding of PVI durability and associated factors.In this regard, it has been elegantly shown in a swine model that elimination of the negative component of the unipolar atrial electrogram during radiofrequency applications reflects transmural lesions creation, whereas the persistence of such a negative component constantly corresponds to nontransmural lesions. 4 We have subsequently reported, in patients affected by paroxysmal AF episodes, the relevance of the atrial unipolar modification analysis as a local ablative end-point while performing PVI and its positive impact in terms of mid-term SR maintenance rate. However and interestingly, this study also has strongly suggested that the elimination of the negative component of the atrial electrogram, although it did not provide histological evidence because it was conducted in humans, may correspond either to transmural but reversible lesions (likely related to edema or transient cell damage) or to transmural and irreversible lesions (likely corresponding to transmural necrosis). 5The aim of the present study is to determine, at the histological level, whether the elimination of the negative component of the atrial electrogram during radiofrequency energy applications might in some circumstances reflect transmural but potentially reversible lesions or it might correspond to transmural and irreversible (necrotic) lesions in others.© 2015 American Heart Association, Inc. Original ArticleBackground-It has been experimentally shown that elimination of the negative component of the unipolar atrial electrogram (R morphology completion) during radiofrequency applications reflects transmural lesions creation. Subsequently, it has been clinically suggested that such a transmurality can be either irreversible or reversible. The present study is aimed to determine, at the histological level, whether transmural lesions, assessed by R morphology completion, might indeed be reversible in some circumstances or not. Methods and Results-In 6 Mongrel hound dogs, superior and inferior vena cavae were isolated and individual lesions were created in the right atrium using radiofrequency energy (30 W/48°C/17 mL/min as presettings and 10g of force in average) under CARTO guidance. Five types of lesions were created; R+0: termination of ablation at the time of R morphology completion; R+5, R+10, or R+20: extension of ablation for 5, 10, or 20 seconds, respectively, after R morphology achievement; and conventional: radiofrequency applications lasting 30 seconds irrespective of the atrial electrogram modification. All conventional, R+5, R+10, and R+20 lesions were necrotic and transmural, whereas some R+0 lesions were not (comprising a part of necrosis and a part of reversible cell damage). Interestingly, surrounding organ injuries were ob...
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