Tau20-RETROmapping System Identifies Driver-Like Activation Patterns in Real Time During Persistent Atrial Fibrillation.

BACKGROUND

Conventional activation mapping of atrial fibrillation (AF) during clinical procedures is limited by low-amplitude, fractionated electrograms and cycle length variability. The Tau20-RETROmapping stimulator-recorder system (TauRhythm Therapies, United Kingdom) is an investigational device used to identify nonpulmonary vein AF drivers by real-time, high-density activation mapping of uniform wavefronts during AF. We validated the accuracy of the system and applied it to left atrial mapping for evidence of AF drivers.

METHODS

Left atrial geometry was acquired using a 3-dimensional electroanatomic mapping system with high-density mapping catheters (CARTO 3 with Optrell, or EnSite X with HD Grid). Electrograms were recorded for 30 seconds at multiple left atrial sites. The Tau20-RETROmapping system generates activation maps of organized wavefronts. System performance was manually validated against randomly sampled local electrograms using a grid sweep of thresholds to identify Pareto-optimal parameters in sinus rhythm, atrial pacing, atrial tachycardia (AT), and AF. The system was then applied to identify putative driver activation patterns during persistent AF.

RESULTS

We studied 24 patients undergoing pulmonary vein isolation for AF. Six patients presented in sinus rhythm or AT, in whom the system demonstrated a sensitivity of 100.0% (95% CI, 80.5%-100.0%) and a specificity of 100.0% (85.2%-100.0%). Eighteen patients were mapped in AF: the system had a sensitivity of 94.4% (86.2%-98.4%) and a specificity of 97.1% (89.9%-99.6%) when identifying organized AF wavefronts, and accurately identified the earliest activation in 89.6% (79.7%-95.7%) of waves. Stable propagation originating from the left atrial appendage (LAA) was observed in 3/18 patients, while 8/18 demonstrated competing propagation toward and away from the LAA. Conduction away from the LAA was detected along the anterior (8/18 patients), lateral (8/18 patients), and posterior (7/18 patients) walls. No propagation near the LAA was observed in 6/18 patients.

CONCLUSIONS

The Tau20-RETROmapping system enables real-time activation mapping of AF, with the most convincing driver-like areas being identified around the LAA.