We have recently shown that a contact force (CF)-guided ablation protocol respecting region-specific criteria of lesion contiguity and lesion depth ('CLOSE' protocol) is associated with high ...incidence of acute durable pulmonary vein (PV) isolation (PVI) and a high single-procedure arrhythmia-free survival at 1 year. In the present study, we compared efficiency, safety, and efficacy of 'CLOSE'-guided PVI to conventional CF-guided PVI (CONV-CF).
Fifty consecutive paroxysmal atrial fibrillation (AF) patients underwent PV encircling using a CF-sensing catheter targeting an interlesion distance (ILD) ≤6 mm and ablation index (AI) ≥400 and ≥550 at posterior and anterior wall ('CLOSE' group). Results were compared to the last 50 patients undergoing 'CONV-CF'. All patients underwent adenosine testing after PVI. Arrhythmia recurrence was defined as any atrial tachyarrhythmia (ATA) >30 s on Holter at 3, 6, and 12 months. Clinical characteristics did not differ. Contact force variability was comparable in between both groups (proportion of applications with intermittent contact 2% in 'CLOSE' vs. 1% in CONV-CF, P = 0.67). In the 'CLOSE' group, procedure time and radiofrequency (RF) time per circle were shorter (respectively 149 ± 33 min vs. 192 ± 42 min, P < 0.0001 and 18 ± 4 min vs 28 ± 7.5 min, P < 0.0001) and incidence of adenosine-proof isolation was higher (97% vs. 82%, P < 0.001). No complications were observed in the 'CLOSE' group, one tamponade in the 'CONV-CF' group. At 12 months, single-procedure freedom from ATA was 94% in 'CLOSE' vs. 80% in 'CONV-CF' group (P < 0.05). In both groups, the majority of reconnections at repeat were associated with either ILD > 6 mm and/or AI < 400/550 (100% vs. 83%, P = 0.99).
'CLOSE'-guided PVI improves procedural and 1 year outcome in CF-guided PVI while shortening procedure time. Improvement cannot be explained by differences in CF variability and is most likely due to the strict application of criteria for contiguity and ablation index. A randomized controlled trial is needed to exclude the possible contribution of a learning curve.
Background
Atrial tachycardia (AT) can be treated by medical or electrical cardioversion but the recurrence rate is high. Three‐dimensional electro‐anatomical mapping, recently described in horses, ...might be used to map AT to identify a focal source or reentry mechanism and to guide treatment by radiofrequency ablation.
Objectives
To describe the feasibility of 3D electro‐anatomical mapping and radiofrequency catheter ablation to characterize and treat sustained AT in horses.
Animals
Nine horses with sustained AT.
Methods
Records from horses with sustained AT referred for radiofrequency ablation at Ghent University were reviewed.
Results
The AT was drug resistant in 4 out of 9 horses. In 8 out of 9 horses, AT originated from a localized macro‐reentrant circuit (n = 5) or a focal source (n = 3) located at the transition between the right atrium and the caudal vena cava. In these 8 horses, local radiofrequency catheter ablation resulted in the termination of AT. At follow‐up, 6 out of 8 horses remained free of recurrence.
Conclusions and Clinical Importance
Differentiation between focal and macro‐reentrant AT in horses is possible using 3D electro‐anatomical mapping. In this study, the source of right atrial AT in horses was safely treated by radiofrequency catheter ablation.
Non-invasive electrocardiogram (ECG) mapping allows the activation of the entire atrial epicardium to be recorded simultaneously, potentially identifying mechanisms critical for atrial fibrillation ...(AF) persistence. We sought to evaluate the utility of ECG mapping as a practical tool prior to ablation of persistent AF (PsAF) in centres with no practical experience of the system.
A total of 118 patients with continuous AF duration <1 year were prospectively studied at 8 European centres. Patients were on a median of 1 antiarrhythmic drug (AAD) that had failed to restore sinus rhythm. Electrocardiogram mapping (ECVUE™, CardioInsight, USA) was performed prior to ablation to map AF drivers (local re-entrant circuits or focal breakthroughs). Ablation targeted drivers depicted by the system, followed by pulmonary vein (PV) isolation, and finally left atrial linear ablation if AF persisted. The primary endpoint was AF termination. Totally, 4.9 ± 1.0 driver sites were mapped per patient with a cumulative mapping time of 16 ± 2 s. Of these, 53% of drivers were located in the left atrium, 27% in the right atrium, and 20% in the anterior interatrial groove. Driver-only ablation resulted in AF termination in 75 of the 118 patients (64%) with a mean radiofrequency (RF) duration of 46 ± 28 min. Acute termination rates were not significantly different amongst all 8 centres (P = 0.672). Ten additional patients terminated with PV isolation and lines resulting in a total AF termination rate of 72%. Total RF duration was 75 ± 27 min. At 1-year follow-up, 78% of the patients were off AADs and 77% of the patients were free from AF recurrence. Of the patients with no AF recurrence, 49% experienced at least one episode of atrial tachycardia (AT) which required either continued AAD therapy, cardioversion, or repeat ablation.
Non-invasive mapping identifies biatrial drivers that are critical in PsAF. This is validated by successful AF termination in the majority of patients treated in centres with no experience of the system. Ablation targeting these drivers results in favourable AF-free survival at 1 year, albeit with a significant rate of AT recurrence requiring further management.
Background
Automated algorithms may identify focal (FA) and rotational (RoA) activations during persistent atrial fibrillation (PeAF).
Objective
To evaluate an automated algorithm for characterizing ...and assessing significance of FA/RoA.
Methods
Eighty‐six PeAF ablation patients (1411 maps) were analyzed. Maps were obtained with a 64‐electrode basket using CARTOFINDER, which filters/annotates atrial unipolar electrograms over 30 seconds. Operators ablated FA/RoA followed by pulmonary vein isolation (PVI). The automated algorithm was retrospectively applied using QS patterns to identify FA and sequential activation gradients for RoA without phase mapping. Algorithm‐identified FA and RoA were validated against blinded adjudicators. Ablation of algorithm‐identified FA/RoA was related to procedural AF termination.
Results
73% ± 18% of electrodes (65% ± 11% atrial surface area) were adequate for analysis. Compared with adjudicators, the algorithm had a sensitivity of 84% for FA and 86% for RoA. There were 4 ± 2 FA and 2 ± 2 RoA per patient. FA occurred 8 ± 6 times during the 30‐second window (cumulative duration 8 ± 6 seconds). RoA occurred 5 ± 3 times (median 2, consecutive rotations) with a cumulative duration of 3 ± 2 seconds. Compared to patients without procedural AF termination, patients with termination had more FA ablated (75% vs 38%, P = 0.006). AF termination was not predicted by percentage of RoA ablated although there was a trend towards a higher percentage of left atrial RoA ablated (
P = 0.06).
Conclusion
An automated algorithm had high sensitivity for FA and RoA. Acute AF termination was associated with FA ablation but not RoA ablation. Future studies need to define the significance of FA and RoA and whether they are overlapping or separate mechanisms.
MRI Assessment of Ablation‐Induced Scarring in Atrial Fibrillation
Background
There is limited knowledge on the extent and location of scarring that results from catheter ablation and its role in ...suppressing atrial fibrillation (AF). We examined the effect of atrial fibrosis and ablation‐induced scarring on catheter ablation outcomes in AF.
Methods
We conducted a prospective multicenter study that enrolled 329 AF patients presenting for catheter ablation. Delayed enhancement magnetic resonance imaging (DE‐MRI) of the left atrium was obtained preablation. Scarring was evaluated in 177 patients with a DE‐MRI scan obtained 90 days postablation. We evaluated residual fibrosis, defined as preablation atrial fibrosis not covered by ablation scar. The primary outcome was freedom from recurrent atrial arrhythmia.
Results
In the analysis cohort of 177 patients, preablation fibrosis was 18.7 ± 8.7% of the atrial wall. Ablation aimed at pulmonary vein (PV) isolation was performed in 163 patients (92.1%). Ablation‐induced scar averaged 10.6 ± 4.4% of the atrial wall. Scarring completely encircled all 4 PVs only in 12 patients (7.3%). Residual fibrosis was calculated at 15.8 ± 8.0%. At 325 days follow‐up, 35% of patients experienced recurrent arrhythmia. Multivariable Cox proportional hazards models demonstrated that baseline atrial fibrosis (HR and 95% CIs) (1.09 1.06–1.12, P < 0.001) and residual fibrosis (1.09 1.05–1.13, P < 0.001) were associated with atrial arrhythmia recurrence, while PV encirclement and overall scar were not.
Conclusions
Catheter ablation of AF targeting PVs rarely achieves permanent encircling scar in the intended areas. Overall atrial fibrosis present at baseline and residual fibrosis uncovered by ablation scar are associated with recurrent arrhythmia.
Networks provide a powerful methodology with applications in a variety of biological, technological and social systems such as analysis of brain data, social networks, internet search engine ...algorithms, etc. To date, directed networks have not yet been applied to characterize the excitation of the human heart. In clinical practice, cardiac excitation is recorded by multiple discrete electrodes. During (normal) sinus rhythm or during cardiac arrhythmias, successive excitation connects neighboring electrodes, resulting in their own unique directed network. This in theory makes it a perfect fit for directed network analysis. In this study, we applied directed networks to the heart in order to describe and characterize cardiac arrhythmias. Proof-of-principle was established using
in-silico
and clinical data. We demonstrated that tools used in network theory analysis allow determination of the mechanism and location of certain cardiac arrhythmias. We show that the robustness of this approach can potentially exceed the existing state-of-the art methodology used in clinics. Furthermore, implementation of these techniques in daily practice can improve the accuracy and speed of cardiac arrhythmia analysis. It may also provide novel insights in arrhythmias that are still incompletely understood.
Achieving block across linear lesions is challenging. We prospectively evaluated radiofrequency (RF) linear ablation at the roof and mitral isthmus (MI) using point-by-point contiguous and optimized ...RF lesions.
Forty-one consecutive patients with symptomatic persistent AF underwent stepwise contact force (CF)-guided catheter ablation during ongoing AF. A single linear set of RF lesions was delivered at the roof and posterior MI according to the 'Atrial LINEar' (ALINE) criteria, i.e. point-by-point RF delivery (up to 35 W) respecting strict criteria of contiguity (inter-lesion distance ≤ 6 mm) and indirect lesion depth assessment (ablation index ≥550). We assessed the incidence of bidirectional block across both lines only after restoration of sinus rhythm. After a median RF time of 7 min interquartile range (IQR) 5-9, first-pass block across roof lines was observed in 38 of 41 (93%) patients. Final bidirectional roof block was achieved in 40 of 41 (98%) patients. First-pass block was observed in 8 of 35 (23%) MI lines, after a median RF time of 8 min (IQR 7-12). Additional endo- and epicardial (54% of patients) RF applications resulted in final bidirectional MI block in 28 of 35 (80%) patients. During a median follow-up of 396 (IQR 310-442) days, 12 patients underwent repeat procedures, with conduction recovery in 4 of 12 and 5 of 10 previously blocked roof lines and MI lines, respectively. No complications occurred.
Anatomical linear ablation using contiguous and optimized RF lesions results in a high rate of first-pass block at the roof but not at the MI. Due to its complex 3D architecture, the MI frequently requires additional endo- and epicardial RF lesions to be blocked.
Introduction
Recent studies have characterized drivers in persistent atrial fibrillation using automated algorithm detection with panoramic endocardial mapping by means of basket catheters. We aimed ...to identify repetitive atrial activation patterns (RAAPs) during ongoing atrial fibrillation (AF) based upon automated annotation of unipolar electrograms (EGMs) recorded with a high‐density regional endocardial contact mapping catheter.
Methods
In 14 persistent AF patients, high‐resolution EGMs were recorded for 30 seconds at sequential PentaRay (Biosense Inc) positions covering the entire biatrial surface. All recordings were reviewed off‐line with dedicated software allowing automated annotation of the local activation time of the unipolar fibrillatory EGMs (CARTOFINDER; Biosense Inc). RAAPs were defined as a consistent activation pattern (for ≥3 consecutive beats) of either focal activity with centrifugal spread (RAAPfocal) or rotational activity across the PentaRay splines spanning the AF cycle length (RAAProtational).
Results
A total of 498 PentaRay recordings were analyzed (35.6 ± 7.6 per patient). The number of PentaRay recordings displaying RAAP was 9.8 ± 3.1 per patient (range = 3‐15), of which 2.4 ± 2.4 RAAProtational (range = 0‐7), and 7.4 ± 4.4 RAAPfocal (range = 1‐13). 77% of RAAPs portrayed focal firing. The median number of repetitions per 30 second recording was 11 (range = 3‐225) per recording. RAAPs were observed both in the right atrium (RA) (35%) and left atrium (LA) (65%), with the majority being near the left PVs/appendage (35% of all RAAPs) and the superior vena cava/right appendage (23% of all RAAPs).
Conclusion
High‐resolution, sequential endocardial EGM‐based mapping allows identification of RAAPs in persistent AF. In our series, focal firing was the most frequently observed pattern.
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