Elimination Of Pulmonary Vein Potentials Research Articles

The identification of conduction gaps after pulmonary vein isolation using a new electroanatomic mapping system

The reconnection of left atrial-pulmonary vein (LA-PV) conduction after the initial procedure of pulmonary vein (PV) isolation is not rare, and is one of the main cause of atrial fibrillation (AF) recurrence after PV isolation. We investigated feasibility of a new ultrahigh-resolution mapping system using a 64-pole small basket catheter for the identification of LA-PV conduction gaps. This prospective study included 31 consecutive patients (20 with persistent AF) undergoing a second ablation after a PV isolation procedure with LA-PV reconnected conduction at any of the 4 PVs. An LA-PV map was created using the mapping system, and ablation was performed at the estimated gap location. The propagation map identified 54 gaps from 39 ipsilateral PV pairs, requiring manual electrogram reannotation for 23 gaps (43%). Gaps at the anterior and carinal regions of left and right ipsilateral PVs required manual electrogram reannotation more frequently than the other regions. The voltage map could identify the gap only in 19 instances (35%). Electrophysiological properties of the gaps (multiple gaps in the same ipsilateral PVs, conduction time, velocity, width, and length) did not differ between those needing and not needing manual electrogram reannotation. During the gap ablation, either the activation sequence alteration or elimination of PV potentials was observed using a circular catheter placed in the PV, suggesting that all the identified gaps were correct. This new electroanatomic mapping system visualized all the LA-PV gaps in patients undergoing a second AF ablation.

Bi-directional block is superior to non-inducibility in predicting freedom from atrial fibrillation after pulmonary vein isolation

There is variability in the endpoints used with the different approaches to pulmonary vein (PV) isolation. Elimination of PVP recorded inside the targeted PV antrum indicates inlet block and is considered the 1st indicator of a successful PV isolation, however this may not be sufficient to predict non recurrence of AF. To compare the efficacy of two end points, pulmonary vein (PV) entrance block with non-inducibility (NI) Vs achieving PV bi-directional (BD) block in terms of freedom of AF after PV isolation (PVI) for paroxysmal/persistent atrial fibrillation (AF). We included 58 consecutive patients (pts) who underwent PVI for symptomatic AF. In all pts, the end point of ablation was abolishing PV potentials (PVP) in the PVs followed by testing for bidirectional block (defined by both loss of PVP and failure to conduct to the LA by pacing at 10 mA and from 10 bipolar pairs of electrodes on a circular catheter positioned at the entrance of the PV) and/or NI of AF (by burst atrial pacing). Bidirectional block was achieved in 40 patients (69%) while Non inducibility was achieved in 36 (58.5%) patients with an overlap of achieving both endpoints in 18 (31%) patients. Over a follow up period of 17 ± 11 months, 34 pts (85%) in group I Vs 22 (62%) in group II were free of AF. Correlation showed significant relation between BD block (OR = 8.07, P = 0.004) Vs NI of AF post-PVI (OR = 2.8, P = 0.095) in predicting freedom from AF at follow up. Achieving BD block improves results and may predict maintenance of sinus rhythm more than NI of AF after PVI. It can be used as an electrophysiological endpoint alternative to or in conjunction with non inducibility in AF ablation procedures.

THE STRATEGY OF CATHETER ABLATION FOR PERSISTENT/PERMANENT ATRIAL FIBRILLATION IN THE PATIENTS WITH IMMEDIATE RECURRENCE AFTER CARDIOVERSION

Abstract Category: Clinical Electrophysiology--Supraventricular ArrhythmiasPresentation Number: 1136-147Authors: Koichi Inoue, Toshiya Kurotobi, Ryusuke Kimura, Yuko Toyoshima, Norihisa Ito, Katsuomi Iwakura, Cardiovascular Center, Sakurabashi-Watanabe Hospital, Osaka, Japan Background: Intensive catheter ablation (CA) of substrates in left atrium (LA) is performed to persistent/permanent atrial fibrillation (peAF). Several mechanisms have been proposed for AF, and unnecessary intensive LA substrate modification could be avoided if the contributing mechanism is specified in each patient.Method: The consecutive 201 patients who underwent circumferential pulmonary vein (PV) isolation to peAF were studied. We performed cardioversion at the beginning of the CA procedure, and observed the presence or absence of immediate recurrence of AF (IRAF), which was defined as AF recurrence within 90 seconds after restoration of sinus rhythm. We followed the patients with IRAF for 14 +/- 8 months, and investigated the incidence of AF recurrence and its mechanism.Result: IRAF was observed in 56 patients (56/202 patients, 28%). All IRAF was triggered by short-coupled premature atrial contractions (PACs). Most of triggering PACs were originated from PVs (52/65 foci, 80%), and 46 out of 56 patients (82%) had PVs which generated the triggering PACs (trigger-PVs). All PVs were successfully isolated during the first procedure. The recurrence was observed in 13 patients (28%) and another session of CA was performed in 10 patients (22%). In these patients, a reconnection of electrical LA-PV conduction was more frequently observed in the trigger-PV than in non-trigger-PV (9/14 PVs (64%) vs. 7/26 PVs (27%), p<0.05). All reconnected PVs were successfully re-isolated, and majority of the patients (41/46 patients, 89%) successfully maintained sinus rhythm.Conclusion: In patients showing IRAF which was triggered by PAC from PVs, the recurrence of AF was mostly due to the restoration of electrical conduction between LA and these PVs. The elimination of PV potentials is especially important, and intensive LA substrate ablation might be unnecessary in these patients.

Elimination of pulmonary vein potentials for catheter ablation of focal atrial fibrillation guided by noncontact mapping: comparison of two different approaches

Elimination of pulmonary vein potentials for catheter ablation of focal atrial fibrillation guided by noncontact mapping: comparison of two different approaches

Treatment of atrial fibrillation with radiofrequency ablation and simultaneous multipolar mapping of the pulmonary veins.

To demonstrate the feasibility and safety of simultaneous catheterization and mapping of the 4 pulmonary veins for ablation of atrial fibrillation. Ten patients, 8 with paroxysmal atrial fibrillation and 2 with persistent atrial fibrillation, refractory to at least 2 antiarrhythmic drugs and without structural cardiopathy, were consecutively studied. Through the transseptal insertion of 2 long sheaths, 4 pulmonary veins were simultaneously catheterized with octapolar microcatheters. After identification of arrhythmogenic foci radiofrequency was applied under angiographic or ultrasonographic control. During 17 procedures, 40 pulmonary veins were mapped, 16 of which had local ectopic activity, related or not with the triggering of atrial fibrillation paroxysms. At the end of each procedure, suppression of arrhythmias was obtained in 8 patients, and elimination of pulmonary vein potentials was accomplished in 4. During the clinical follow-up of 9.6+/-3 months, 7 patients remained in sinus rhythm, 5 of whom were using antiarrhythmic drugs that had previously been ineffective. None of the patients had pulmonary hypertension or evidence of stenosis in the pulmonary veins. Selective and simultaneous catheterization of the 4 pulmonary veins with microcatheters for simultaneous recording of their electrical activity is a feasible and safe procedure that may help ablation of atrial fibrillation.

Catheter Ablation of Chronic Atrial Fibrillation Targeting the Reinitiating Triggers

We assessed the mode of reinitiation of atrial fibrillation (AF) after cardioversion and the efficacy of ablating these foci of reinitiation in patients with chronic AF. Fifteen patients, 7 with structural heart disease, underwent mapping and catheter ablation of drug-resistant AF documented to be persistent for 5 +/- 4 months. In all patients, cardioversion was followed by documentation of P on T atrial ectopy and early recurrence, which allowed mapping of the reinitiating trigger or the source of ectopy. Radiofrequency (RF) ablation was performed at pulmonary vein (PV) ostia using a target temperature of 50 degrees C and a power limit of 30 to 40 W, with the endpoint being interruption of all local muscle conduction. A total of 32 arrhythmogenic PVs and 2 atrial foci (left septum and left appendage) were identified: 1, 2, and 3 or 4 PVs in 5, 3, and 6 patients. RF applications at the ostial perimeter resulted in progressively increasing delay, followed by abolition of PV potentials in 8, but potentials persisted in 6. A single ablation session was performed in 7 patients and 8 underwent two or three sessions because of recurrence of AF; ablation was directed at the same source due to recovery of local PV potential or at a different PV. No PV stenosis was noted either acutely or at repeated follow-up angiograms. Nine patients (60%) were in stable sinus rhythm without antiarrhythmic drugs at follow-up of 11 +/- 8 months. Anticoagulants were interrupted in 7 patients. PVs are the dominant triggers reinitiating chronic AF in this patient population. Elimination of PV potentials by ostial RF applications results in stable sinus rhythm in 60%. A larger group and longer follow-up are needed to investigate further the role of trigger ablation in curative therapy for chronic AF.