Characterization of Focal Atrial Tachycardia Using High-Density Mapping

Characterization of Focal Atrial Tachycardia Using High-Density Mapping Prashanthan Sanders, Mélèze Hocini, Pierre Jaïs, Li-Fern Hsu, Yoshihide Takahashi, Martin Rotter, Christophe Scavée, Jean-Luc Pasquié, Fréderic Sacher, Thomas Rostock, Chrishan J. Nalliah, Jacques Cleménty, Michel Haïssaguerre Focal atrial tachycardias are characterized by atrial activity that originates from a small area (focus) and spreads out centrifugally. Mapping to identify these focal arrhythmias can be difficult. In this study, the role of high-density localized mapping to identify and characterize the origin of focal atrial tachycardia is evaluated. High-density localized mapping enables rapid vector mapping to identify the site of earliest activation. Localized mapping at the origin of some of these apparently “focal” atrial tachycardias demonstrated localized re-entry. The goal of this study was to characterize the origin of focal atrial tachycardias (AT). Focal ATs originate from a small area and spread centrifugally; however, activation at the AT origin has not been characterized. Twenty patients with AT having failed prior ablation or occurring after atrial fibrillation ablation were studied. After excluding macro–re-entry, AT was mapped using a 20-pole catheter (five radiating spines; diameter 3.5 cm), performing vector mapping to identify the earliest activity followed by high-density mapping at the AT origin. Localized re-entry was considered if >85% of the tachycardia cycle length (CL) was observed within the mapping field and was confirmed by entrainment. A total of 27 ATs were mapped to the pulmonary vein ostia (n = 5), and left (n = 16) and right atria (n = 6). A localized focus was evidenced at the site of origin in 19 ATs (70%), whereas in 8 (30%), localized re-entry was evidenced by 95.2 ± 4.5% of the tachycardia CL recorded within the mapping field and entrainment showed a post-pacing interval