Emily Keating

A Novel Mapping System for Panoramic Mapping of the Left Atrium: Application to Detect and Characterize Localized Sources Maintaining AF

Objectives This study sought to use a novel panoramic mapping system (CARTOFINDER) to detect and characterize drivers in persistent atrial fibrillation (AF). Background Mechanisms sustaining persistent AF remain uncertain. Methods Patients undergoing catheter ablation for persistent AF were included. A 64-pole basket catheter was used to acquire unipolar signals, which were processed by the mapping system to generate wavefront propagation maps. The system was used to identify and characterize potential drivers in AF pre- and post-pulmonary vein (PV) isolation. The effect of ablation on drivers identified post-PV isolation was assessed. Results Twenty patients were included in the study with 112 CARTOFINDER maps created. Potential drivers were mapped in 19 of 20 patients with AF (damage to the basket and noise on electrograms was present in 1 patient). Thirty potential drivers were identified all of which were transient but repetitive; 19 were rotational and 11 focal. Twenty-six drivers were ablated with a predefined response in 22 of 26 drivers: AF terminated with 12 and cycle length slowed (≥30 ms) with 10. Drivers with rotational activation were predominantly mapped to sites of low-voltage zones (81.8%). PV isolation had no remarkable impact on the cycle length at the driver sites (138.4 ± 14.3 ms pre-PV isolation vs. 137.2 ± 15.2 ms post-PV isolation) and drivers that had also been identified on pre-PV isolation maps were more commonly associated with AF termination. Conclusions Drivers were identified in almost all patients in the form of intermittent but repetitive focal or rotational activation patterns. The mechanistic importance of these phenomena was confirmed by the response to ablation.

A Novel Mapping System for Panoramic Mapping of the Left Atrium: Application to Detect and Characterize Localized Sources Maintaining Atrial Fibrillation

Objectives This study sought to use a novel panoramic mapping system (CARTOFINDER) to detect and characterize drivers in persistent atrial fibrillation (AF). Background Mechanisms sustaining persistent AF remain uncertain. Methods Patients undergoing catheter ablation for persistent AF were included. A 64-pole basket catheter was used to acquire unipolar signals, which were processed by the mapping system to generate wavefront propagation maps. The system was used to identify and characterize potential drivers in AF pre- and post-pulmonary vein (PV) isolation. The effect of ablation on drivers identified post-PV isolation was assessed. Results Twenty patients were included in the study with 112 CARTOFINDER maps created. Potential drivers were mapped in 19 of 20 patients with AF (damage to the basket and noise on electrograms was present in 1 patient). Thirty potential drivers were identified all of which were transient but repetitive; 19 were rotational and 11 focal. Twenty-six drivers were ablated with a predefined response in 22 of 26 drivers: AF terminated with 12 and cycle length slowed (≥30 ms) with 10. Drivers with rotational activation were predominantly mapped to sites of low-voltage zones (81.8%). PV isolation had no remarkable impact on the cycle length at the driver sites (138.4 ± 14.3 ms pre-PV isolation vs. 137.2 ± 15.2 ms post-PV isolation) and drivers that had also been identified on pre-PV isolation maps were more commonly associated with AF termination. Conclusions Drivers were identified in almost all patients in the form of intermittent but repetitive focal or rotational activation patterns. The mechanistic importance of these phenomena was confirmed by the response to ablation.

Panoramic atrial mapping with basket catheters: A quantitative analysis to optimize practice, patient selection, and catheter choice

Panoramic mapping with basket catheters has been used to map atrial fibrillation (AF). However, the limited tissue contact and coverage achieved has raised concerns.

Validation of a novel mapping system and utility for mapping complex atrial tachycardias

This study sought to validate a novel wavefront mapping system utilizing whole‐chamber basket catheters (CARTOFINDER, Biosense Webster). The system was validated in terms of (1) mapping atrial‐paced beats and (2) mapping complex wavefront patterns in atrial tachycardia (AT).

Characterization of drivers maintaining atrial fibrillation: Correlation with markers of rapidity and organization on spectral analysis

BACKGROUNDnBetter characterization of drivers in atrial fibrillation (AF) may facilitate their identification.nnnOBJECTIVEnThe purpose of this study was to demonstrate that certain driver characteristics are associated with greater mechanistic importance in maintaining AF.nnnMETHODSnPersistent AF was mapped in patients using the CARTOFINDER system with a 64-pole basket catheter to identify and ablate drivers with rotational or focal activity after pulmonary vein isolation. An ablation response was defined as cycle length (CL) slowing ≥30 ms or AF termination. Driver sites with an ablation response were correlated to sites of fastest CL, highest dominant frequency (DF), and greatest organization (lowest cycle length variability [CLV] and highest regularity index [RI]). Parameters predicting AF termination with driver ablation were evaluated.nnnRESULTSnAll 29 patients had ≥1 driver identified. Forty-four potential drivers were identified. The predefined ablation response occurred with 39 drivers (89%): 23 rotational and 16 focal. During a 30-second recording, each driver occurred 8.7 ± 5.4 times and completed 3.1 ± 0.9 consecutive repetitions per occurrence. Driver sites correlated best with markers of organization, corresponding to the site of lowest CLV (29/39 [74%]) and highest RI (26/39 [67%]). Correlation with sites of fastest CL and highest DF was poor (17/39 and 15/39, respectively) and depended on driver temporal stability. Greater temporal stability (3.4 ± 0.9 vs 2.7 ± 0.6; P = .001) and driver correlation with sites of lowest CLV and highest RI (both Pxa0<.001) predicted AF termination with ablation.nnnCONCLUSIONnIntermittent focal or rotational drivers were identified in all patients. Drivers consistently correlated to organization markers. Greater temporal stability and organization predicted AF termination with driver ablation.

Structural remodeling and conduction velocity dynamics in the human left atrium: Relationship with reentrant mechanisms sustaining atrial fibrillation

Background Rate-dependent conduction velocity (CV) slowing is associated with atrial fibrillation (AF) initiation and reentrant mechanisms. Objective The purpose of this study was to assess the relationship between bipolar voltage, CV dynamics, and AF drivers. Methods Patients undergoing catheter ablation for persistent AF (<24 months) were enrolled. Unipolar electrograms were recorded with a 64-pole basket catheter during atrial pacing at 4 pacing intervals (PIs) during sinus rhythm. CVs were measured between pole pairs along the wavefront path and correlated with underlying bipolar voltage. CV dynamics within low-voltage zones (LVZs <0.5 mV) were compared to those of non-LVZs (≥0.5 mV) and were correlated to driver sites mapped using CARTOFINDER (Biosense Webster). Results Eighteen patients were included (age 62 ± 10 years). Mean CV at 600 ms was 1.59 ± 0.13 m/s in non-LVZs vs 0.98 ± 0.23 m/s in LVZs (P <.001). CV decreased incrementally over all 4 PIs in LVZs, whereas in non-LVZs a substantial decrease in CV was only seen between PIs 300–250 ms (0.59 ± 0.09 m/s; P <.001). Rate-dependent CV slowing sites measurements, defined as exhibiting CV reduction ≥20% more than the mean CV reduction seen between PIs 600–250 ms for that voltage zone, were predominantly in LVZs (0.2–0.5 mV; 75.6% ± 15.5%; P <.001). Confirmed rotational drivers were mapped to these sites in 94.1% of cases (sensitivity 94.1%, 95% CI 71.3%–99.9%; specificity 77.9%, 95% CI 74.9%–80.7%). Conclusion CV dynamics are determined largely by the extent of remodeling. Rate-dependent CV slowing sites are predominantly confined to LVZs (0.2–0.5 mV), and the resultant CV heterogeneity may promote driver formation in AF.

Automated detection of repetitive focal activations in persistent atrial fibrillation: Validation of a novel detection algorithm and application through panoramic and sequential mapping: HONARBAKHSH et al.

Identifying drivers in persistent atrial fibrillation (AF) remains challenging. We sought to validate an automated system for detection of focal activation using basket and PentaRay catheters in AF.

Sinus node modification utilising a novel multi electrode catheter with orthogonal wavefront mapping

An 18-year-old female with Ehlers Danlos syndrome and severely intrusive symptoms related to inappropriate sinus tachycardia (IST) despite multiple medications had previously undergone 2 sinus node modifications with limited success. The first procedure used cryo-ablation and the second radiofrequency ablation. Despite intra procedural heart rate slowing, patient symptoms recurred soon after the ablation and she was scheduled for a repeat attempt at sinus node modification using a novel multi electrode mapping catheter. A zero fluoroscopy case was performed using the Precision/ NavX system (Abbott, USA). Initial right atrial geometry was initially collected with a Tacticath (F-curve) irrigated 4mm ablation catheter (Abbott, USA). A quadripolar catheter was placed in coronary sinus and a novel 16-polar multi electrode catheter (high density, HD grid, Abbott, USA) used for further geometry collection alongside rapid point collection for simultaneous activation times and a voltage map. A total of 931 points were taken during the map (<5 minutes). Baseline sinus rhythm cycle length was 750m s. Previous ablation lesions denoted by low voltage were noted in the high right atrium (Fig. 1A). During sinus rhythm the earliest signal