Anatomical Ablation Research Articles

In memory of tachycardia: A wide complex tachycardia in a young male.

We present a case of a 24‐year‐old male with palpitations and a wide complex tachycardia. Baseline electrocardiogram (ECG) after termination of tachycardia demonstrates a normal rhythm but with inferior/anterolateral T‐wave inversions (TWIs). Electrophysiologic study confirmed the diagnosis of posterior fascicular ventricular tachycardia successfully terminated by anatomic ablation of the left posterior fascicle. TWIs on the patient's baseline ECG were consistent with cardiac memory.

P1009Procedural success and long-term outcome of CTI ablation targeted with maximum voltage-guided approach: preliminary results from an Italian multicenter registry

Abstract Background Ablation technique targeting high-amplitude signals (maximum voltage guided - MVG -) on the cavotricuspid isthmus (CTI) has emerged as viable alternative option compared to standard anatomical approach (ST) for the creation of bidirectional conduction block (BDB) across the isthmus but limited data are available to date. Purpose To evaluate the effectiveness of acute and long-term outcome of CTI ablation through MVG technique for AFL compared to standard linear (SL) lesion ablation. Methods Atrial Flutter Ablation in a Real World Population (LEONARDO) is a prospective, multicenter cohort study aimed at providing an estimate of acute to long-term outcome in a large population of patients (pts) indicated for AFL ablation. Recurrence of AFL were retrieved at 12-month follow-up. Complete BDB was defined by agreement with the presence of widely split double potentials (DP) along the ablation line and assessment of the atrial activation sequence (AAS). For MVG technique the ablation catheter was positioned at the site of maximum local electrogram voltage. Results Two-hundred fifteen consecutive pts were included (mean age 68 years, 73% male). A median of 4 [2–6] ablation lesions were required. Median follow up was 359 [192–443] days. Complete BDB was achieved in 175 (81.4%) pts (9 pts had DP only criterion, 30 pts had AAS only criterion whereas in 1 pt we failed to reach a BDB). In the 106 pts with complete data at 1-year follow-up, 10 (9.4%) had a recurrence of AFL. 171 pts (79%) underwent a SL ablation whereas 44 pts (21%) were treated by MVG approach. The median number of lesions/pt was significantly lower in the group of pts targeted with MVG compared to the SL approach (3 [2–4] vs 4 [2–8], p<0.01), whereas no differences were found in terms of fluoroscopy time (16 [12–18] min vs 12 [7–22] min, p=NS) or proportion of pts with BDB achievement (86.4% of the cases for MVG vs 80.1% of the cases for ST, p=NS). No complications were reported. AFL recurrence was comparable during follow-up between groups (8.3% for MVG vs 9.8% for SL ablation; p=NS). Conclusion Ablation of a targeted site through MGV approach seems to be safe and effective as standard anatomical ablation technique. This strategy may avoid unnecessary ablation of the entire anatomic isthmus. Acknowledgement/Funding None

A safe and simple approach to avoid fast junctional rhythm during ablation in patients with atrioventricular nodal reentrant tachycardia.

Fast junctional rhythm (JR) during slow pathway modification for atrioventricular nodal reentrant tachycardia (AVNRT) is a predictor of serious atrioventricular block. This study investigated the boundary to avoid fast JR during ablation with three-dimensional (3D) electroanatomical mapping in AVNRT patients. Participants were 129 consecutive patients with common AVNRT who received anatomical ablation to an antegrade slow pathway at our institution between August 2013 and March 2019. Successfully ablated sites with JR were evaluated in terms of distances and angles in the left and right anterior oblique views (LAO and RAO, respectively) to the proximal His bundle (His) site using 3D mapping. We divided JR by heart rate: JR1 ≥150 bpm and JR2 <150 bpm. Average age was 61 ± 16 years; 41.1% of patients were male. The distance from the most proximal His to the JR1 and JR2 site was not significantly different (11.9 ± 4.4 vs 10.7 ± 4.5 mm, P = .24). JR1 predominantly appeared closer to the left ventricle than JR2 in LAO (110.5 ± 19.1° vs 77.5 ± 18.6°, P < .01), and was more posterior from the proximal His in RAO (30.8% vs 6.8%, P < .01). The vertical line drawn down from the proximal His in the LAO view was a good indicator of JR1 appearance (sensitivity and specificity 84.6% and 81.6%, respectively). The vertical line drawn down from the proximal His in the LAO view can be employed as a boundary to avoid fast JR during ablation in AVNRT.

MARSHALL bundles elimination, Pulmonary veins isolation and Lines completion for ANatomical ablation of persistent atrial fibrillation: MARSHALL-PLAN case series.

Beyond pulmonary veins (PV) isolation, the ablation strategy for persistent atrial fibrillation (AF) remains controversial. Substrate ablation may provide a high termination rate but at the cost of impaired atrial physiology and recurrent complex re-entries. To overcome these pitfalls, we investigated a new lesion set based on important anatomical considerations. The case series included 10 consecutive patients with persistent AF. Three atrial structures were successively targeted: (1) coronary sinus and vein of Marshall (CS-VOM) musculature elimination; (2) PVs isolation; and (3) anatomical isthmuses block. The lesion set completion was the procedural endpoint. Step 1: VOM ethanol infusion was feasible in all cases (mean time of 33.4 ± 9.4 minutes), mean radiofrequency(RF) time for CS-VOM bundles was 14.4 ± 6.9 minutes. Step 2: mean RF time for PV isolation was 27.7 ± 9.3 minutes. Step 3: mean RF time for mitral, roof, and cavotricuspid lines was 5.7 ± 2.3, 8.1 ± 4.3, and 5.9 ± 1.9 minutes, respectively. The lesion set was achieved in all patients. Mean procedure time was 270 ± 29.9 minutes. AF termination and noninducibility were, respectively, obtained in 50% and 90% of the patients. After a 6-month follow-up, all patients were free from arrhythmia recurrence. The present case series reports a new ablation strategy systematically targeting anatomical structures previously identified as possibly involved in the fibrillatory process and the recurrent tachycardias. The resulting lesion set provides good short-term outcomes. Although promising, these preliminary results need to be confirmed in the larger prospective study.

Ganglionated plexi ablation with pulmonary vein isolation after testing dormant pulmonary vein conduction and excluding non-pulmonary triggers in patients with paroxysmal atrial fibrillation

Background. Pulmonary vein isolation (PVI) is the gold standard of interventional atrial fibrillation (AF) treatment, however, it doesn't provide a stable clinical effect and durable PVI in the long-term follow-up due to reconnections within the ablation line. To increase the efficacy of surgery, modulation of the autonomic nervous system can be combined with pulmonary vein isolation.Aim. The study was focused on the evaluation of efficacy of ganglionated plexi (GP) ablation combined with PVI, and intraoperative drug testing of dormant pulmonary vein conduction and exclusion of non-pulmonary vein triggers in patients with paroxysmal atrial fibrillation.Methods. There hundred sixty-seven patients with paroxysmal AF scheduled for catheter ablation were initially screened. PVI was performed in all patients. After testing with adenosine triphosphate and isoprenaline for dormant conduction following PVI and exclusion of non-pulmonary vein triggers, 194 patients with a positive response to high-frequency stimulation in the main GP sites of the left atrium were randomized in two groups: PVI (group I, n = 97), PVI with anatomical GP ablation (group II, n = 97). To perform continuous ECG monitoring, 53 patients received implantable cardiac monitors. The primary endpoint of the study was the freedom from any atrial tachyarrhythmias after 12 months of follow- up as recorded by 24-hour Holter monitoring. The secondary endpoints included AF burden based on implantable cardiac monitors data and predictors of AF recurrences. The patients were followed 3, 6, 9, 12 months after the ablation procedure.Results. The mean follow-up was 12.5±2.2 months. By the end of the follow-up, 79 (81.4%) patients in the PVI with GP ablation group and 58 (59.8%) patients in the PVI only group were free from any atrial tachyarrhythmia (р=0.0012; log-rank test, HR 0.41, 95% CI [0.23–0.72], р=0.002; Cox regression). Implantable cardiac monitors data revealed that AF burden was significantly lower in the PVI with GP group as compared with the PVI only group (14.8±1.7% and 5.4±0.7%, р&lt;0.001). According to the multivariable regression analysis, the independent predictors of AF recurrences were AF duration and presence of diabetes mellitus, while GP ablation reduced the risk of AF recurrence by 61%.Conclusion. Ganglionated plexi ablation combined with pulmonary vein isolation confirmed by testing dormant conduction and excluding non-pulmonary triggers provides higher efficacy in maintaining the sinus rhythm as compared with PVI only in patients with paroxysmal atrial fibrillation. Received 17 July 2018. Revised 7 August 2018. Accepted 10 August 2018. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest. Author contributionsConception and study design: Yu.S. Krivosheev, L.I. Vilenskiy, V.N. KolesnikovData collection and analysis: Yu.S Krivosheev, D.I. Bashta, A.A. SimonyanDrafting the article: Yu.S. Krivosheev, A.A. Simonyan, D.I. Bashta, S.Yu. KrasilnikovaCritical revision of the article: V.N. KolesnikovFinal approval of the version to be published: Yu.S. Krivosheev, D.I. Bashta, A.A. Simonyan, S.Yu. Krasilnikova, L.I. Vilenskiy, T.A. Myznikova, Z.A. Mishodzheva, V.N. Kolesnikov

5-Year Outcome of Pulmonary Vein Isolation by Loss of Pace Capture on the Ablation Line Versus Electrical Circumferential Pulmonary Vein Isolation

This study sought to compare long-term arrhythmia-free survival between electrical circumferential pulmonary vein isolation (PVI) and PVI with the endpoint of unexcitability along the ablation line. PVI is the standard ablation strategy of paroxysmal atrial fibrillation, although arrhythmia recurrence in long-term follow-up (FU) is high. The endpoint of unexcitability along the ablation line results in decreased arrhythmia recurrence compared to electrical PVI in 1-year FU. Seventy-four consecutive patients (age 62.5 ± 10.6 years; 70.3% male) with de novo paroxysmal atrial fibrillation who were initially included in our randomized trial and underwent catheter ablation at our institution were analyzed. Patients who were randomized to either a conventional group (PVI, guided by circumferential catheter signals) or a pace-guided group (PG, anatomical ablation line encircling, ablation until loss of pace capture at 10 V, 2-ms pulse width on the ablation line) underwent long-term FU. The primary endpoint was recurrence of any atrial fibrillation or atrial tachycardia after a blanking period of 3 months. Sixty-nine patients completed a mean FU period of 5.14 ± 0.98 years. Arrhythmia-free survival without antiarrhythmic drug therapy was significantly higher in the PG group (71.05% vs. 25.81%, p= 0.002). Furthermore, multiple procedure success (1.29 ± 0.61 procedures in PG vs. 1.97 ± 1.06 procedures in conventional group, p< 0.001) was higher in the PG group compared to the conventional group (89.47% vs. 58.06%, p= 0.005). The endpoint of unexcitability along the PVI line improves success rates, resulting in a significant reduction of exposure to invasive procedures in 5-year FU.

P372Automated low intensity collimated ultrasound 3D anatomic mapping and ablation system minimizes need for continuous operator engagement

P372Automated low intensity collimated ultrasound 3D anatomic mapping and ablation system minimizes need for continuous operator engagement

Efficacy of an Anatomical Approach in Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Outflow Tract.

When anatomic obstacles preclude radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT), an alternative approach from the anatomically opposite side (endocardial versus epicardial or above versus below the aortic valve) may be considered (anatomic ablation). The purpose of this study was to investigate the efficacy of an anatomic ablation in idiopathic LVOT VAs. We studied 229 consecutive patients with idiopathic LVOT VAs. Radiofrequency ablation from the first suitable site was successful in 190 patients, and in the remaining 39 patients, it was unsuccessful or had to be abandoned because of anatomic obstacles. In 22 of these 39 patients, an anatomic ablation was successful, and the VA origins were located in the intramural LVOT in 17 patients, basal left ventricular summit in 4, and LVOT septum near the His bundle in 1. The anatomic ablation was highly successful for idiopathic VAs originating from the intramural LVOT (>75%) and lateral LVOT, whereas it was unlikely to be successful for idiopathic VAs originating from the basal left ventricular summit (25%) and sepal LVOT. When a standard catheter ablation targeting the best electrophysiological measure of idiopathic LVOT VAs was unsuccessful or had to be abandoned because of anatomic obstacles, an anatomic ablation was moderately successful. These idiopathic LVOT VAs with a successful anatomic ablation commonly arose from the intramural LVOT among the left coronary cusp, aortomitral continuity, and epicardium, occasionally the basal left ventricular summit, and rarely the LVOT septum near the His bundle.

Atrial Ganglionated Plexus Modification: A Novel Approach to Treat Symptomatic SinusBradycardia.

This study sought to determine if anatomic atrial ganglionated plexus (GP) ablation leads to long-term sinus rate (SR) increase and improves quality of life in patients with symptomatic sinus bradycardia (SB). Atrial GP ablation has been demonstrated to increase SR in our previous study. Atrial GP ablation may also be effective in treating patients with symptomatic SB. Sixty-two patients with symptomatic SB were recruited: Group A included patients<50 years of age (n=40); Group B included patients≥50 years of age (n= 22). All patients underwent anatomic ablation of the main atrial GP, and 24-h Holter monitoring and quality-of-life assessment were performed during 1 year of follow-up. Quality of life was accessed by the Medical Outcomes Study Short-Form 36 Health Survey. Although SR markedly increased in all patients after GP ablation, the increase was significantly greater in patients<50 years of age than in patients≥50 years of age (19.3 ± 9.9 beats/min vs. 10.8 ± 5.4 beats/min; p= 0.001). The right anterior GP and the GP at the junction of the aorta and superior vena cava made the greatest contributions to SR increase among all GP. The mean and minimal SR increased significantly after ablation and remained elevated for 12months only in Group A patients. Although symptoms and quality of life improved in all patients, 5 of the 8 domains of the Medical Outcomes Study Short-Form 36 Health Survey did not show obvious improvements in patients of Group B at 12 months. Anatomic atrial GP ablation effectively increased SR and improved quality of life in patients <50years of age with symptomatic SB.

Impact of Contact Force Monitoring in Acute Pulmonary Vein Isolation Using an Anatomic Approach. A Randomized Study.

The impact of contact force (CF) monitoring in pulmonary vein (PV) isolation after a circumferential anatomic ablation (CAA) is unknown. We analyze the usefulness of CF monitoring in acute PV isolation and procedure parameters using a CAA. Fifty patients with paroxysmal atrial fibrillation were randomized into CF-on (CF >10 grams; n = 25) or CF-off (CF blinded; n = 25) groups. We performed a first round of CAA with a ThermoCool(®) SmartTouch(®) catheter blinded to the LASSO(®) catheter (Biosense Webster, Diamond Bar, CA, USA), with radiofrequency (RF) lesions tagged with the VisiTag(™) Module. After the CAA, each PV was reviewed with the LASSO(®) catheter recording the segments with gaps. All the PVs were isolated with a CAA in 20 patients of the CF-on versus eight of the CF-off (P = 0.001). Of the 45 segments with gaps in the left PVs, 38 were from the CF-off (P = 0.0001). Of the eight segments with gaps in the right PVs, seven were from the CF-off (P = 0.06). The CF in the left PVs was higher in the CF-on (16.3 ± 3.2 grams vs 10.5 ± 4.3 grams; P = 0.0001) and similar in the right PVs (17.6 ± 3.6 grams vs 15.2 ± 5.3 grams; P = 0.08). All of the gaps were closed with additional RF LASSO(®) -guided touch-up. Procedure and fluoroscopy times were shorter in the CF-on (139 ± 24 minutes vs 157 ± 32 minutes and 20 ± 6 minutes vs 24 ± 7 minutes; both P = 0.039). At 12 months the patients free of AF recurrence was 84% CF-on versus 75% CF-off (log-rank P = 0.4) [corrected]. In paroxysmal atrial fibrillation, a CAA guided by CF reduces PV gaps and shortens the procedure parameters at the expense of the left PVs.

Evaluation of proarrythmogenic effects after different techniques of radiofrequency catheter ablation of atrial fibrillation

To assess proarrythmogenic effects after different techniques of radiofrequency catheter ablation, 427 patients with paroxysmal, persistent, and long-standing persistent atrial fibrillation (AF) were examined. The patients were randomized into four groups: antral pulmonary vein isolation (PVI) (Group I), PVI plus roof line and mitral isthmus ablation (Group II), anatomic ablation of ganglionated plexuses (GP) of the left atrium (Group III) and GP plus PVI (Group IV). At the end of follow up (34,43,2 months) the largest number of proarrythmogenic effects was observed in Group II, 24,8% (26 patients). In the remaining groups the percentage of proarrythmogenic effects did not exceed 11%, neither was there any significant difference among Groups I, III and IV. Thus, the creation of additional linear lesions in the left atrium is a predictor of proarrythmogenic effects during follow up.

The rotor revolution: conduction at the eye of the storm in atrial fibrillation.

The recent explosion of literature on rotors in human atrial fibrillation (AF) is no surprise to followers of the history of science in which return to an old paradigm paradoxically heralds incremental progress based on the emergence of new evidence. Although the rotor paradigm is neither confirmed nor universal, it does revitalize a more mechanistic approach to addressing persistence in human AF. Although determining the relevance of rotors is the current obsession, we must reach beyond this existential debate and focus on the underpinning mechanisms. Critical to this is understanding how the underlying tissue architecture governs conduction and is manifest in electrograms and their spatiotemporal distribution and how therefore the hierarchical rotor paradigm can be unified with the anarchical paradigm of diffuse, widely distributed complex microreentry. It is the challenge of unifying these apparently irreconcilable bodies of evidence that is the stimulus for reviewing the areas of mechanistic importance common to the relationship between myocardial architecture and conduction that lies at the heart of understanding persistence in human AF. The rotor revolution has focussed attention on conduction characteristics that promote drivers as the underlying mechanism of persistence and increasing refractoriness to treatment of AF. This has shifted thinking away from a purely anatomic ablation strategy to a mechanistic one based on propagation mapping. Regardless of the discussion surrounding how rotors are detected and whether therefore they exist at all, mechanisms are now in fashion again. Although rotors are the paradigm of the moment,1 the debate with proponents of multiple wavelet reentry rages with renewed vigor, but unlike previously at stake now are the procedural outcomes and the welfare of our patients. Whatever the macroscopic panoramic pattern of activation, no coherent explanation exists for how rotors may result from the causative myocardial remodeling at the cellular and tissue level. In …

Exploration of Theoretical Ganglionated Plexi Ablation Technique in Atrial Fibrillation Surgery

Ganglionated plexi ablation during atrial fibrillation surgery is not technically standardized for precise ganglionated plexi locations or ablation sequence. We aimed to identify precise active ganglionated plexi locations in patients with structural heart disease and explore the feasibility of anatomic ganglionated plexi ablation without prior mapping in patients with atrial fibrillation. Thirty patients with valvular disease-associated atrial fibrillation underwent ganglionated plexi ablation and a modified maze procedure. In 20 patients, ganglionated plexi mapping was performed to identify active plexi. According to mapping results, anatomically determined plexi were ablated without mapping in the final 10 patients. Ganglionated plexi ablation outcomes with and without prior mapping were compared between perioperative and early postoperative periods. Active ganglionated plexi common to more than 20% of patients were identified in the superior and inferior right pulmonary veins, superior left pulmonary vein, interatrial groove, and inferior left atrium. Inferior left atrial plexi ablation resulted in maximum vagal modulation. Compared with ablation using mapping, anatomic ablation yielded more vagal modulation in heart rate variability and decreased the requisite cardiopulmonary bypass time. The sequential pacing and ablation technique identified an optimal ablation sequence that best ensured vagal reflex elimination from all ganglionated plexi. Anatomic ablation using a predetermined ganglionated plexi map may be a viable alternative to individual plexus mapping before ablation.

EP News: Clinical

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).

Preformed Wolffian duct regulates Müllerian duct elongation independently of canonical Wnt signaling or Lhx1 expression.

The Müllerian duct gives rise to female reproductive organs, such as the oviduct and uterus. During gestation, the Wolffian duct, which generates male reproductive organs and the kidney, is formed, and the Müllerian duct then elongates caudally along the preformed Wolffian duct. Anatomical separation of these two ducts in chick embryos demonstrated that the Wolffian duct is required for Müllerian duct formation. Likewise, a few reports supported this notion in mice, including studies on Wnt9b mutant mice and Wolffian duct-specific Lhx1 deletion. However, anatomical ablation of the Wolffian duct has not been established in mice. In this study, we addressed the importance of the interaction between these two reproductive ducts, by generating mice that specifically expressed a diphtheria toxin subunit in the Wolffian duct. While this genetic ablation of the Wolffian duct resulted in kidney hypoplasia/agenesis in both male and female mutant mice, the female mutant mice lacked the uterus, which is derived from the Müllerian duct. At mid-gestation, the Müllerian duct was truncated at the level where the mutant Wolffian duct was prematurely terminated, meaning that Müllerian duct elongation was dependent on the preformed Wolffian duct. However, Wnt9b expression in the Wolffian duct and the resultant canonical Wnt activity, as well as Lhx1 expression, were not affected in the mutant mice. These results suggest that the Wolffian duct regulates Müllerian duct elongation by currently unidentified mechanisms that are independent of canonical Wnt signaling or Lhx1 expression.

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.

Direct or Coincidental Elimination of Stable Rotors or Focal Sources May Explain Successful Atrial Fibrillation Ablation: On-Treatment Analysis of the CONFIRM Trial (Conventional Ablation for AF With or Without Focal Impulse and Rotor Modulation)

This study sought to determine whether ablation of recently described stable atrial fibrillation (AF) sources, either directly by Focal Impulse and Rotor Modulation (FIRM) or coincidentally when anatomic ablation passes through AF sources, may explain long-term freedom from AF. It is unclear why conventional anatomic AF ablation can be effective in some patients yet ineffective in others with similar profiles. The CONFIRM (Conventional Ablation for AF With or Without Focal Impulse and Rotor Modulation) trial prospectively revealed stable AF rotors or focal sources in 98 of 101 subjects with AF at 107 consecutive ablation cases. In 1:2 fashion, subjects received targeted source ablation (FIRM) followed by conventional ablation, or conventional ablation alone. We determined whether ablation lesions on electroanatomic maps passed through AF sources on FIRM maps. Subjects who completed follow-up (n = 94; 71.2% with persistent AF) showed 2.3 ± 1.1 concurrent AF rotors or focal sources that lay near pulmonary veins (22.8%), left atrial roof (16.0%), and elsewhere in the left (28.2%) and right (33.0%) atria. AF sources were ablated directly in 100% of FIRM cases and coincidentally (e.g., left atrial roof) in 45% of conventional cases (p < 0.05). During a median (interquartile range) of 273 days (138 to 636 days) after one procedure, AF was absent in 80.3% of patients if sources were ablated but in only 18.2% of patients if sources were missed (p < 0.001). Freedom from AF was highest if all sources were ablated, intermediate if some sources were ablated, and lowest if no sources were ablated (p < 0.001). Elimination of stable AF rotors and focal sources may explain freedom from AF after diverse approaches to ablation. Patient-specific AF source distributions are consistent with the reported success of specific anatomic lesion sets and of widespread ablation. These results support targeting AF sources to reduce unnecessary ablation, and motivate studies on FIRM-only ablation.

“Largest Amplitude Ablation” is the Optimal Approach for Typical Atrial Flutter Ablation: A Subanalysis from the AURUM 8 Study

The recently proposed "maximum voltage-guided" (MVG) technique for radiofrequency catheter ablation of atrial flutter targets high-voltage electrograms along cavotricuspid isthmus (CTI) to ablate the functionally important anatomic muscle bundles alone, without drawing a complete anatomic line across the CTI. This innovative approach may shorten ablation time and procedure duration. Within the multicenter AURUM 8 study, which compared 8-mm gold- and Pt-Ir-tip catheters in atrial flutter ablation, we made a post hoc comparison of procedural data from 72 patients treated with MVG technique with data from 281 patients undergoing anatomic CTI ablation (unmatched) and with data from 72 patients selected from among those 281 patients such that they were matched with the MVG group with respect to selected baseline parameters and catheter type (matched). The MVG technique markedly reduced (P < 0.001) ablation time (mean 6.9 minutes vs 10.9/9.7 minutes [unmatched/matched]), number of lesions (8.3 vs 13.7/12.9), fluoroscopy time (9.5 minutes vs 20.6/17.9 minutes), procedure duration (59 minutes vs 93/86 minutes), and energy delivered (19 kJ vs 34/30 kJ) compared with anatomic CTI ablation. The incidence of charring was higher for MVG than for anatomic ablation technique (31.9% vs 18.5/15.3%, P < 0.05), where Pt-Ir tip catheters were 6-fold more susceptible to charring than gold-tip catheters (P < 0.001), likely because of a lower thermal conductivity of the Pt-Ir material. The acute success rate was slightly better for MVG than for anatomic ablation technique (97.2% vs 92.2/91.7%, P = n.s.). Major procedural parameters are remarkably improved with MVG technique. Gold-tip catheters are substantially less susceptible to charring and may therefore be preferred over Pt-Ir-tip catheters for MVG ablation technique.

Catheter Ablation of Right Atrial Ganglionated Plexi in Patients With Vagal Paroxysmal Atrial Fibrillation

Catheter ablation of ganglionated plexi (GP) in the left atrium has been proposed in different subgroup of patients with atrial fibrillation (AF). Anatomic studies found a high prevalence of GP in the posterior surface of the right atrium (RA). Experimental data suggested the potential role of right atrial GP in the AF initiation and maintenance. The aim of our study was to assess the efficacy of GP ablation in RA in patients with vagal AF. Thirty-four patients without structural heart diseases were randomly assigned for a selective ablation procedure targeted on the elimination of vagal reflex evoked by high frequency stimulation or an extensive approach at anatomic sites of GP. All patients underwent Holter ECG and heart rate variability evaluation at baseline and at 3, 6, 12, and 18 months of follow-up. At a mean follow-up of 19.7±5.2 months, AF recurred in 5 of 17 patients with anatomic ablation and in 13 of 17 patients with a selective approach (P=0.01). No patient had major complications. After ablation, heart rate variability parameters showed a significant parasympathetic (and sympathetic) denervation in the first 6 months, which was more prominent in patients with anatomic GP ablation and in those without AF recurrence. This study demonstrates that in a selected population of vagal paroxysmal AF, the anatomic ablation of GPs in the RA is effective in about 70% of patients. These results confirm that atrial vagal denervation can abolish AF, as suggested by experimental and clinical data.

Predictors of AF Termination during Ablation Procedure and Freedom from AF Recurrence after Anatomical Linear Ablation in Longstanding, Persistent AF

Background: There are controversies regarding the predictors of AF termination during AF substrate ablation and freedom from the recurrences during the post-ablation follow-up period in longstanding, persistent AF (LPAF). Methods and Results: Consecutive 254 patients with LPAF (AF duration (AFD): 81±101 months, LA diameter (LAD): 47±1015 mm) underwent initial ablation session for extensive PV isolation and anatomical linear ablation with procedural endpoint of AF elimination. AF termination (n=23) or conversion to atrial tachycardia (AT) (n=63) or flutter (n=22) was achieved in 108 patients (42.5%; Group-1), while AF persisted after completion of the ablation protocol in the remaining 146 patients (57.5%; Group-2). Comparison of baseline characteristics showed significant differences in AFD (68±10187 vs. 91±101109 months; P=0.03), LAD (46±1015 vs. 48±1015 mm; P<0.01) and baseline AF cycle length (183±10135 vs. 171±10135 msec; P=0.02) between Group-1 vs. Group-2, respectively. Two hundred and six patients were followed beyond the blanking period (2 months) for 417±101236 days after the initial procedure. Among the 206 patients, 108 were free from AF/AT recurrence (Group-A), while the other 98 had AF/AT recurrence (Group-B). Comparison of baseline characteristics showed significant differences in AFD (62±10170 vs. 86±10198 months; P=0.02) and LAD (46±1015 vs. 48±1016 mm; P=0.02) between Group-Avs. Group-B, respectively. Multivariate analysis identified AFD as an independent predictor of both AF elimination during ablation procedure and freedom from AF/AT recurrence after the procedure (P<0.003 for both) and AF elimination during ablation procedure as that of freedom from AF/AT recurrence after the procedure (P<0.03). Conclusions: The results of this study suggest AF elimination during ablation procedure predicts favorable post-ablation outcomes and AFD is an important limiting factor when ablation is indicated in LPAF patients.