Pace Mapping for the Identification of Focal Atrial Tachycardia Origin: A Novel Technique to Map and Ablate Difficult-to-Induce and Nonsustained Focal Atrial Tachycardia

Background - Focal atrial tachycardia (FAT) is extremely difficult to map and ablate when it is difficult to induce and nonsustained. The objective of this study is to evaluate the efficacy of pace mapping in identifying the FAT origin. Methods and Results - The study included 7 patients with drug-refractory FAT who experienced daily multiple episodes before ablation and presented with difficult-to-induce and nonsustained FAT and a distinct P wave morphology. Pace mapping was systematically performed in the areas of interest using 3-dimensional mapping to match the P wave morphology and paced intracardiac activation sequence recorded from multiple catheters. The anatomic origins of FAT were the right pulmonary vein (PV) in 3 patients, mitral annulus, crista terminalis, tricuspid annulus, and right-sided PV via a posterior conduction of previous PV isolation. In all patients, pace mapping obtained best-matched P wave morphology in â\u89¥11/12 leads of surface ECG at the successful ablation site, and paced intracardiac activation sequence was identical to that of induced FAT. Focal ablation was delivered in 4 patients, including non-PV FAT in 3 and FAT in 1, via posterior gap along the previous right-sided PV isolation, and circumferential right-sided PV isolation was performed in the other 3 patients. No FAT was induced at the end of the procedure. All patients were free of arrhythmias without antiarrhythmic drugs during the 8.4±5.6-month follow-up. Conclusions - The combination of paced P wave morphology and intracardiac activation sequence can be used for the identification of FAT origin in patients with difficult-to-induce and nonsustained FAT

First clinical experience using a novel high-resolution electroanatomical mapping system for left atrial ablation procedures

Background: The Rhythmia mapping system was recently launched and allows for rapid ultra-high-resolution electroanatomical mapping. We evaluated the feasibility, acute efficacy and safety of this novel system for ablation of atrial fibrillation (AF) and left atrial (LA) tachycardia (AT). Methods and results: A total of 35 consecutive patients (age 64.3 ± 8.6 years, LA diameter 44.4 ± 5.8 mm) underwent catheter ablation for AF and/or AT. All procedures were performed using Rhythmia in conjunction with the Orion mini-basket catheter. Pulmonary vein isolation (PVI) and linear lesions were performed applying radiofrequency (RF) energy. PVI was confirmed by presence of entrance and exit block using the mini-basket catheter. In addition, pacing maneuvers assessed bidirectional conduction block across linear lesions. Procedure duration was 110.3 ± 33 min, fast acquisition mapping (FAM) time was 19 ± 9 min. A mean number of 10165 ± 5904 mapping points were acquired during the initial map and 6379 ± 3191 for a remap. A total number of 31 ± 15 RF applications were delivered within 45 ± 22 min. Total fluoroscopy time was 21 ± 5, 5 ± 2 min were used for FAM. We observed a significant learning curve for mapping duration (p = 0.01). Complications included pericardial tamponade (n = 1), transient air embolism in the right coronary artery (n = 1), and mild groin hematoma (n = 2). Conclusions: The present study is the largest to describe experience of LA ablation procedures using Rhythmia. PVI was achieved in all patients. Applying this ultra high-resolution electroanatomical mapping system under routine conditions leads to a high level of confidence. More data will be mandatory before final conclusions can be drawn

Bonus-freeze: benefit or risk? Two-year outcome and procedural comparison of a "bonus-freeze" and "no bonus-freeze" protocol using the second-generation cryoballoon for pulmonary vein isolation

Background: Second-generation cryoballoon based pulmonary vein isolation has demonstrated encouraging acute and mid-term clinical outcome. Customarily, a bonus-freeze is applied after successful pulmonary vein isolation. Objective: To compare the long-term clinical outcome and safety profile of a bonus-freeze and a no bonus-freeze protocol. Methods: A total of 120 consecutive patients with paroxysmal [95/120 (79 %)] or persistent atrial fibrillation [25/120 (21 %)] underwent CB2-based PVI. Freeze-cycle duration was 240 s. In the first 60 patients a bonus-freeze was applied after successful PVI (group 1), while in the following 60 patients the bonus-freeze was omitted (group 2). Results: Procedure and fluoroscopy times were significantly shorter in group 2 [113.8 ± 32 vs 138.2 ± 29 min (p = 0.03) and 19.2 ± 6 vs 24.3 ± 8 min (p = 0.02)]. No differences in procedural complications were found. During a mean follow-up of 849 ± 74 (group 1) and 848 ± 101 days (group 2, p = 0.13) 69 % of patients (group 1) and 67 % of patients (group 2) remained in stable sinus rhythm without any differences between the groups (p = 0.69). Conclusions: Freedom from atrial fibrillation after second-generation cryoballoon based pulmonary vein isolation and a follow-up of >2 years is comparable when applying a bonus- and a no bonus-freeze protocol, while procedure and fluoroscopy times are significantly shorter when omitting the bonus-freeze. No differences in periprocedural complications were identified

Catheter ablation of atrial fibrillation in very young adults: a 5-year follow-up study

Catheter ablation is an established therapy for symptomatic atrial fibrillation (AF). However, outcome data on catheter ablation for AF in young adults is scarce. From 2005-2014, 85 consecutive young adults (mean age 31±4 years; 69% men) with symptomatic paroxysmal AF (PAF, n = 52) and persistent (Pers) AF (n = 33) underwent pulmonary vein isolation (PVI) [±ablation of complex fractionated atrial electrograms/linear lesions in PVI non-responders] at our centre. Follow-up was based on outpatient visits including 24-h Holter-ECG at 3, 6 and, 12 months post ablation, and every 12 months thereafter. Recurrence was defined as any AF/atrial tachycardia episode >30s following a 3-month blanking period. Follow-up was available for 74/85 (87%) patients. After a median follow-up of 4.6 years (Q1: 2.6; Q3: 6.6) and a mean of 1.5±0.6 (median 1, range 1-3) ablation procedures 84% [including 13% on previously ineffective antiarrhythmic drugs (AAD)] of patients were in stable SR. Single-procedural 1-year/5-year arrhythmia-free survival was 66% [95% confidence interval (CI): 56-78%]/44% (95% CI: 33-59%), respectively. Structural heart disease [SHD; hazard ratio (HR) 2.79 (95% CI 1.52-5.12), P = 0.001] and obesity [HR 1.10 (95% CI 1.00-1.21) per unit increase in body mass index >27 kg/m2, P = 0.05] independently predicted AF recurrence. Major complications occurred in 6/122 (4.9%) procedures (PV stenosis in 3, cardiac tamponade in 1, stroke in 1, and arterial-venous fistula in 1). In the majority of very young adults catheter ablation for AF is effective, and associated with an acceptable complication rate. SHD and obesity are predictors for AF recurrence in this population