Abstract
BACKGROUND: The use of intracardiac electrograms to guide atrial fibrillation (AF) ablation has yielded conflicting results. OBJECTIVES: The authors evaluated the usefulness of spatiotemporal dispersion, a visually recognizable electric footprint of AF drivers, for the ablation of all forms of AF. METHODS: The authors prospectively enrolled 105 patients admitted for AF ablation. AF was sequentially mapped in both atria with a 20-pole PentaRay catheter. The authors tagged and ablated only regions displaying electrogram dispersion during AF. Results were compared to a validation set in which a conventional ablation approach was used (pulmonary vein isolation/stepwise approach). To establish the mechanism underlying spatiotemporal dispersion of AF electrograms, the authors conducted realistic numerical simulations of AF drivers in a 2-dimensional model and optical mapping of ovine atrial scar-related AF. RESULTS: Ablation at dispersion areas terminated AF in 95% of the 105 patients. After ablation of 17 ± 10% of the left atrial surface and 18 months of follow-up, the atrial arrhythmia recurrence rate was 15% after 1.4 ± 0.5 procedures per patient versus 41% in the validation set after 1.5 ± 0.5 procedures per patient (arrhythmia free-survival: 85% vs. 59%; log-rank p < 0.001). Compared with the validation set, radiofrequency times (49 ± 21 min vs. 85 ± 34.5 min; p = 0.001) and procedure times (168 ± 42 min vs. 230 ± 67 min; p < 0.0001) were shorter. In simulations and optical mapping experiments, virtual PentaRay recordings demonstrated that electrogram dispersion is mostly recorded in the vicinity of a driver. CONCLUSIONS: The clustering of intracardiac electrograms exhibiting spatiotemporal dispersion is indicative of AF drivers. Their ablation allows for a nonextensive and patient-tailored approach to AF ablation. (Substrate Ablation Guided by High Density Mapping in Atrial Fibrillation [SUBSTRATE HD]; NCT02093949).