Circumferential Antral Ablation Research Articles

High density mapping guided partial antral ablation for a pulmonary vein isolation

The muscular discontinuities at the pulmonary vein (PV)–left atrial (LA) junction are known. The high-density mapping may help to find the muscular discontinuity. This study evaluated the efficacy of a partial antral ablation for a pulmonary vein (PV) isolation using high density (HD) mapping. A total of 60 drug-refractory atrial fibrillation (AF) patients undergoing catheter ablation were enrolled. The detailed activation mapping of each PV and LA junction was performed using an HD mapping system, and each PV segment’s activation pattern was classified into a “directly-activated from the LA” or “passively-activated from an adjacent PV segment” pattern. The antral ablations were performed at the directly-activated PV segments only when the PV had “passively-activated segments”. If the PV did not contain passively-activated segments, a circumferential antral ablation was performed on those PVs. A “successful partial antral ablation” was designated if the electrical isolation of targeted PV was achieved by ablation at the directly-activated segments only. If the isolation was not achieved even though all directly-activated segments were ablated, a “failed partial antral ablation” was designated, and then a circumferential ablation was performed. Among 240 PVs, passively-activated segments were observed in 140 (58.3%) PVs. Both inferior PVs had more passively-activated segments than superior PVs, and the posteroinferior segments had the highest proportion of passive activation. The overall rate of successful partial antral ablation was 85%. The atrial tachyarrhythmia recurrence was observed in 10 patients (16.7%) at 1-year. HD mapping allowed the evaluation of the detailed activation patterns of the PVs, and passively-activated segments may represent muscular discontinuity. Partial antral ablation of directly-activated antral segments only was feasible and effective for a PVI.

Pulmonary veins isolation in a patient with atrial fibrillation and pronounced vagal response: Is it enough?

Introduction. Pulmonary vein isolation (PVI) by antral circumferential ablation is the standard procedure for patients with symptomatic and drug-refractory paroxysmal atrial fibrillation (AF). In some patients addition of ganglionated plexi (GP) modification in anatomic locations to PVI confers significantly better outcomes than PVI alone. Case report. We reported a patient with paroxysmal, symptomatic AF and severe bradycardia a month prior to ablation. The patient was treated with antiarrhythmic drugs without success. Because of severe bradicardia the patient was implanted with a temporary pace maker two days before PVI. During PVI the decision was made to also do a modification of the left GP. Three months after the procedure the patients was in stable sinus rhythm without any symptoms. Conclusion. In selected patients with paroxysmal AF and pronounced vagal response PVI by circumferential antral ablation combined with GP modification during single ablation procedure can produce higher success rates than PVI or GP ablation alone.

Left atrial anatomy, atrial fibrillation burden, and P-wave duration-relationships and predictors for single-procedure success after pulmonary vein isolation.

Atrial fibrillation (AF) is associated with changes in left atrial (LA) volume, but the relationship between LA size, AF burden, and electrical conduction behaviour is still uncertain. The aim of this study was to quantify the association and impact of these parameters on the single-procedure outcome after circumferential antral ablation for pulmonary vein isolation. Left atrial assessment was performed in 129 consecutive patients using pre-procedural imaging in three dimensions (sphericity, indexed volume), two dimensions (diameters), and from echocardiography in one dimension (long axis). Atrial fibrillation burden was classified based on the clinical assessment as paroxysmal and persistent and based on a validated scoring system including frequency, duration of AF episodes, and number of cardioversions into four grades (minimal, mild, moderate, and severe). P-wave duration and PR interval was measured on the 12-lead electrocardiogram at the end of the procedure. Atrial fibrillation burden score (AFB) was minimal (2%), mild (75%), moderate (9%), and severe (14%) and 65% had paroxysmal and 35% had persistent AF. The recurrence rate was significantly higher in patients with persistent AF, with higher AFB, with prolonged P-wave, and with an indexed LA volume > 55 mL/m2. In multivariable analysis, AFB (hazard ratio: 2.018(1.383-2.945), P > 0.001) and a prolonged P-wave (hazard ratio: 2.612(1.248-5.466), P = 0.011) were identified as significant predictors for AF recurrence. In our cohort of patients with symptomatic AF, the AFB and the P-wave duration but none of the anatomical parameter revealed to be independent predictors for AF/AT recurrence after circumferential antral pulmonary vein isolation.

Lower rate of left atrial tachycardia after pulmonary vein isolation with PVAC versus irrigated-tip circumferential antral ablation

Left atrial tachycardias (LAT) occur in about 5% of patients after irrigated-tip circumferential antral (CA) pulmonary vein isolation (PVI). They may cause debilitating symptoms in the patient and may be very difficult to treat. To assess the incidence of LAT after PVI with the multielectrode phased-radiofrequency pulmonary vein ablation catheter (PVAC) compared to circumferential antral PVI with an irrigated-tip catheter. We analyzed data from our ablation database. A total of 150 patients who underwent their first PVI with the PVAC system and 300 patients who underwent their first PVI with irrigated-tip circumferential antral (CA) radiofrequency ablation were matched by age and sex, as well as by type of atrial fibrillation. Of 150 PVAC patients, only 1 patient (0.7%) developed LAT during mean follow-up of 21 ± 14 months. The mechanism was macroreentry and the patient underwent successful ablation at our institution. Eleven of 300 irrigated-tip CA PVI patients (3.7%) developed LAT during mean follow-up of 22 ± 14 months and subsequently underwent ablation (P = .05). LAT occurs more frequently after irrigated-tip CA PVI compared to single-shot-device ablation with PVAC. Apart from being less technically demanding, lower incidence of LAT may influence choice of ablation technology.

Pulmonary Vein Isolation With Incomplete Antral Ablation Lines: Is More Ablation Necessary? Results of a Randomized Trial.

A full circumferential set of antral lesions is not always required for bidirectional pulmonary vein conduction block. It is unknown whether a partial lesion set that isolates the veins will have clinical success rates similar to a full circumferential lesion set, and if procedural times or procedural risk will be affected. We performed a prospective, randomized clinical trial to test the hypothesis that a partial lesion set that isolates the pulmonary veins has comparable clinical success rate and shorter procedure times compared to a strategy of completing the circumferential lesion set once the veins are isolated. A total of 119 patients were enrolled, 59 randomized to circumferential ablation, and 60 to segmental. Mean age was 58.3 ± 10.1, 77% male. Mean procedure time was 221.0 ± 46.9 minutes in circumferential and 224.7 ± 51.3 in segmental (P = 0.68). Twelve-month freedom from AF recurrence was 61.3% overall, 64.4% in circumferential, and 58.3% in segmental (P = 0.50). Among 25 segmental patients with AF recurrence, 23 underwent second ablation. Among 33 areas of conduction recovery, 23 (70%) occurred in segments ablated at first procedure and 10 (30%) in segments not previously ablated, suggesting reversible conduction block from edema. No difference in AF recurrence or procedure time is detectable in a sample of 119 patients randomized to segmental or circumferential antral ablation to achieve pulmonary vein isolation. Second ablation procedures confirmed that some antral sites do not require ablation. A segmental approach results in unacceptably high rates of untargeted or recovered antral sites to make this approach feasible.

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Katritsis et al (J Am Coll Cardiol 2013;62:2318, PMID 23973694) investigated whether conventional pulmonary vein isolation (PVI) through circumferential antral ablation with ganglionated plexus (GP) modification in a single ablation procedure yields higher success rates than does PVI or GP ablation alone. Two hundred forty-two patients with paroxysmal atrial fibrillation were randomized to (1) circumferential PVI (n = 78), (2) anatomic ablation of the main left atrial GP (n = 82), or (3) circumferential PVI followed by anatomic ablation of the main left atrial GP (n = 82).

Autonomic Denervation Added to Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation: A Randomized Clinical Trial

The aim of this study was to investigate whether the combination of conventional pulmonary vein isolation (PVI) by circumferential antral ablation with ganglionated plexi (GP) modification in a single ablation procedure, yields higher success rates than PVI or GP ablation alone, in patients with paroxysmal atrial fibrillation (PAF). Conventional PVI transects the major left atrial GP, and it is possible that autonomic denervation by inadvertent GP ablation plays a central role in the efficacy of PVI. A total of 242 patients with symptomatic PAF were recruited and randomized as follows: 1) circumferential PVI (n = 78); 2) anatomic ablation of the main left atrial GP (n = 82); or 3) circumferential PVI followed by anatomic ablation of the main left atrial GP (n = 82). The primary endpoint was freedom from atrial fibrillation (AF) or other sustained atrial tachycardia (AT), verified by monthly visits, ambulatory electrocardiographic monitoring, and implantable loop recorders, during a 2-year follow-up period. Freedom from AF or AT was achieved in 44 (56%), 39 (48%), and 61 (74%) patients in the PVI, GP, and PVI+GP groups, respectively (p = 0.004 by log-rank test). PVI+GP ablation strategy compared with PVI alone yielded a hazard ratio of 0.53 (95% confidence interval: 0.31 to 0.91; p = 0.022) for recurrence of AF or AT. Fluoroscopy duration was 16 ± 3 min, 20 ± 5 min, and 23 ± 5 min for PVI, GP, and PVI+GP groups, respectively (p < 0.001). Post-ablation atrial flutter did not differ between groups: 5.1% in PVI, 4.9% in GP, and 6.1% in PVI+GP. No serious adverse procedure-related events were encountered. Addition of GP ablation to PVI confers a significantly higher success rate compared with either PVI or GP alone in patients with PAF.

Incidence, characteristics, and outcome of left atrial tachycardias after circumferential antral ablation of atrial fibrillation

Antral pulmonary vein isolation (PVI) for treatment of atrial fibrillation may induce left atrial tachycardias (ATs). To determine the prevalence, time course of occurrence, mechanisms, and correlation with the electrocardiogram as well as the outcome of ablation of these tachycardias. Out of the 839 patients who underwent circumferential antral radiofrequency PVI guided by a circumferential pulmonary vein catheter at our institution between February 2005 and April 2011, 35 patients (4%) developed AT during follow-up. Six patients with left AT and a previous PVI at other institutions were also included. Of these 41 patients (26 men, 63%; age 59 ± 10 years), 26 (63%) had underlying paroxysmal atrial fibrillation and 15 (37%) had persistent atrial fibrillation. AT ablation was performed 47 ± 60 weeks after initial PVI, within the first 3 months in 16 patients (39%). The tachycardia mechanism was focal in 15 patients (37%), macroreentry in 25 patients (61%), and undetermined in 1 (2%). Focal tachycardias had an isoelectric line between distinct P waves in 13 of the 15 patients (87%), while only 4 (16%) with a macroreentrant mechanism had an isoelectric line (P <.001). Although difficult to measure, a P-wave width of >140 ms had the highest sensitivity and specificity to identify macroreentrant mechanism. Ablation was acutely successful in 32 patients (78%) and not successful in 4 (10%). In 5 patients, success could not be determined as the tachycardia terminated or degenerated during mapping. During a mean follow-up of 31 ± 17 months, 11 patients (27%; n = 9 [82%] with macroreentry) underwent repeat ablation procedure for AT. Eight patients had true recurrence, for example, the same AT, and 3 patients had a second mechanism of AT. With the use of an identical ablation protocol, it was found that approximately 4% of the patients developed AT after mere circumferential antral PVI. The majority of ATs developed within a few months after ablation but occurred as late as several years after the initial PVI. Macroreentry was more frequent than a focal mechanism. Broad P waves and isoelectric lines between P waves help to distinguish a focal mechanism from a macroreentrant mechanism. Ablation has a high acute success rate, and AT recurrence occurs predominantly in macroreentrant AT.

Complete antral encirclement is not required for pulmonary vein isolation

Complete circumferential antral ablation may not be necessary for successful pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (AF). We examined the feasibility of a noncircumferential approach limited to segments of the antra required for PV-atrial conduction. During ablation for paroxysmal AF, each PV antrum was divided into six segments, and ablation was sequentially targeted to antral segments with the earliest activity until bidirectional isolation was achieved. Ablation at the ostium was avoided. Patients requiring complete circumferential ablation (circumferential group) were compared with those undergoing incomplete antral ablation (noncircumferential group) with respect to freedom from symptomatic atrial arrhythmia, procedure, and ablation times. Ninety-nine patients underwent ablation with successful isolation of PVs (n = 37 circumferential; n = 62 noncircumferential). There were no significant differences in age, gender, AF duration, or LA size. Procedure time (202 ± 45 vs. 185 ± 47 minutes; P = .06) and ablation time (51 ± 15 vs. 41 ± 14 minutes; P = .004) were shorter in the noncircumferential group. During follow-up (12 ± 6 months), freedom from symptomatic recurrence was 73% in both groups (P = .97), with organized atrial tachycardia being more common in the circumferential group (P = .06). In 22 patients undergoing repeat study, PV reconnection was demonstrated in 82% and 81% of PVs in each group. Reconnection in the noncircumferential group occurred in previously ablated segments in 10 (77%) of 13 cases. Noncircumferential antral ablation achieves similar success rates with shorter procedure and ablation times than circumferential ablation. Greater attention should be focused on producing permanent lesions rather than on completing antral encirclement after isolation is achieved.

On the Use of CartoSound for Left Atrial Navigation

The utility of "virtual" imaging systems for left atrial (LA) navigation has been hampered by inadequate spatial detail, as well as inaccurate integration of more detailed preoperative images, such as those generated by computed tomography (CT). CartoSound is an intracardiac echocardiography (ICE)-based technology that promises to ameliorate these problems. Our objective was to examine the capabilities and optimal use of CartoSound, both as a stand-alone tool and as a facilitator of CT image integration. In 10 patients, CartoSound models of the LA were generated using each of 4 ICE transducer locations: LA, right atrium (RA), coronary sinus (CS), and esophagus (ESO). Each of these models was used to register CT-derived LA models into the operative workspace. We correlated the comprehensiveness of LA imaging from each transducer location with the quality of the CT registration, as well as the accuracy of mock circumferential antral ablation guided by the CartoSound model alone or by the CT model. The LA transducer location provided the most comprehensive rendering of the LA, which was associated with higher quality CT registration and greater CT-guided mock ablation accuracy. Mock ablation guided by the CartoSound model alone was at least as accurate as CT, although the models were less intuitive. For LA navigation, optimal use of CartoSound may require LA transducer location, which is effective for stand-alone use and as a facilitator of CT image integration.

Pulmonary vein isolation by duty-cycled bipolar and unipolar antrum ablation using a novel multielectrode ablation catheter system: first clinical results

The electrical disconnection of the pulmonary veins (PV) plays an important role in the ablation strategy of paroxysmal atrial fibrillation (PAF). Circumferential antral ablation with a conventional ablation technique using a steerable ablation catheter is sometimes difficult to perform and does not always result in isolation of the targeted PV. Patients with symptomatic PAF were treated with a novel circular mapping/ablation catheter (PVAC). Ablation was performed in the antral region of the PV with a power-modulated bipolar/unipolar RF generator using 8-10 W until isolation of the vein was achieved. Seven-day Holter monitor recordings were performed off antiarrhythmic drugs at 3 and 6 months after the initial procedure. A subgroup of patients had received an implantable recorder before ablation, and the device was interrogated at the same time. The primary objective of this study is acute isolation of the targeted PV, and the second objective is clinical efficacy with a short-term follow-up. In 73 patients, 290 PV could be reached with the PVAC. Antral ablation was performed in 244 PV showing PV potentials. Acutely, 243 PV (99%) were isolated with the PVAC after 21+/-7 energy applications per patient with a mean fluoroscopy time of 20+/-11 min. Total procedure time was 122+/-27 min. No complications were observed. Follow-up at 3 and 6 months showed freedom from AF in 61 of 73 (84%) patients and 38 of 45 patients (85%), respectively, off antiarrhythmic drugs. PV isolation by duty-cycled unipolar/bipolar RF ablation can be effectively and safely performed with a circular, decapolar catheter. Clinical results at 3 and 6 months after ablation are encouraging with the need for longer follow-up intervals.

Anatomical analysis of recurrent conduction after circumferential ablation

There is general agreement on the importance of electrical isolation of antral (including pulmonary vein) myocardium for effective atrial fibrillation (AF) ablation. However, isolation is often impermanent, and return of conduction (RoC) is associated with recrudescent AF. It is generally assumed that the mechanism of RoC is recovery of ablated myocardium, but this is based almost solely on experience after ablation at the venoatrial junctions. Our objective was to perform an anatomical analysis as a means to gain further insight into RoC risk factors and mechanism(s) after wide-area circumferential ablation. Retrospective review of data from 512 consecutive patients who underwent wide-area circumferential antral ablation. After achieving left and right antral electrical isolation, each patient underwent a period of observation for RoC during this initial procedure. In addition, 76 of the 512 patients underwent a repeat procedure at an average of 10 months later, at which time they were again assayed for RoC. Left or right antral RoC was observed in 39 (8%) or 21 (4%) patients, respectively, during the initial procedure, and 26 (34%) or 16 (21%) patients, respectively, during the repeat procedure. Left antral RoC was more commonly observed among patients manifesting a long segment separating the circumferential lesion and the venoatrial junctions, and usually occurred in this segment, often at sites distant from ablated sites. Right antral RoC commonly occurred in the anterior and superior antral regions, also often at sites that were distant from ablated sites. In the left antrum, there was a correlation between electrophysiologic (RoC) and anatomic (long segment) properties. The observation in both antra that RoC often occurred in previously unablated areas suggested that, as an alternative to recovery of ablated myocardium, a second mechanism of RoC was plausible: conduction via unablated myocardium, which was not immediately manifest. These observations have compelled us to modify our circumferential lesion.

Clinical Significance of Complete Conduction Block of the Left Lateral Isthmus and Its Relationship with Anatomical Variation of the Vein of Marshall in Patients with Nonparoxysmal Atrial Fibrillation

The vein of Marshall (VOM), which exists along the left lateral isthmus (LLI), constitutes a muscular connection between the coronary sinus (CS) and the left atrium (LA). We hypothesized that anatomical variation of the VOM affects the bidirectional block of LLI and the clinical outcome in patients with nonparoxysmal atrial fibrillation (NPAF). Among 73 patients with NPAF, 54 patients (47 male, 54.1 +/- 10.4 years old) with a clearly visible VOM (74.0%) were included. After circumferential antral ablation, double linear endocardial ablation of LLI was performed along the VOM. Unless LLI block was achievable by endocardial ablation, the ablation was performed inside the CS. LLI block was achievable in 35 patients (64.8%; 11.1% by endocardial ablation vs 53.7% by additional inside CS ablation; P < 0.01). In patients with failed LLI block, the VOM was significantly longer (P < 0.05) on the right anterior oblique (RAO) view than in those with successful LLI block. LA volume or LLI length measured by CT image were not different (P = NS). During 11.4 +/- 5.0 months follow-up, early recurrences within 3 months (47.4% vs 28.6%, P = NS) and recurrences after 3 months (10.5% vs 17.7%, P = NS) were not different with or without LLI block. LLI block, which is more difficult to achieve in patients with a longer VOM, was achievable in 65% of patients with NPAF by linear ablation along the VOM and additional inside CS ablation, but did not affect the short-term clinical outcome.

Pulmonary vein isolation predicts freedom from arrhythmia after circumferential antral ablation for paroxysmal atrial fibrillation

The aims of this observational study were to evaluate (i) the feasibility of obtaining bidirectional pulmonary vein (PV) isolation by means of circumferential radiofrequency ablation of the antral aspect of the PV ostium; (ii) whether the electrophysiological demonstration of bidirectional PV isolation predicts freedom from atrial tachyarrhythmia recurrence after ablation in patients with paroxysmal atrial fibrillation. The study group comprised 28 patients affected by frequent recurrences of paroxysmal atrial fibrillation refractory to antiarrhythmic drugs, who underwent transcatheter ablation of the PVs by means of a non-fluoroscopic navigation system. Radiofrequency pulses were delivered in a point-by-point fashion at the antral aspect of the ostium of each vein presenting distal PV potentials. After ablation of each PV, bidirectional isolation was tested by means of a basket catheter. No antiarrhythmic drugs were prescribed on discharge. Outpatient visits, 24-h electrocardiographic Holter monitoring, and continuous 7-day digital electrocardiogram were scheduled at 3, 6, and 12 months. A distal potential was detected in 101/123 (82%) mapped PVs. Bidirectional isolation was obtained in 81/101 (80%) PVs; bidirectional isolation of all targeted PVs was obtained in 17 (61%) patients. After a mean follow-up of 12.2 +/- 4.2 months, clinical success was observed in 15 (53%) patients. On multivariate analysis, only bidirectional isolation of all targeted PVs predicted the clinical success of ablation (P < 0.003; hazard ratio 7.504; confidence interval 1.943-28.990). Circumferential antral ablation achieves bidirectional isolation in 80% of PVs. Bidirectional isolation of all PVs is essential to curing patients with paroxysmal atrial fibrillation.