Abstract 13901: Significance of Rotor Activation Observed Outside of the Pulmonary Vein for the Maintenance of Atrial Fibrillation: Three-dimensional Analysis Using a Non-contact Mapping System

Abstract

Background: It has been suggested pulmonary vein (PV) acts as the driving sources of atrial fibrillation (AF). However, it is unclear whether the rotor, which is located outside the PV, also maintains the AF. Objectives: To define the prevalence and significance of rotor observed outside the PV in the left atrium (LA), LA activation sequence was analyzed during AF after PV isolation. Methods: Endocardial mapping of LA was performed in 25 AF patients (9 paroxysmal and 16 persistent AF) using a non-contact mapping system (EnSite 3000) during AF perpetuated after PV isolation. Presence of rotor activation was defined when the circular activation around the functional block line once completed its whole reentrant activation. To define the role of rotor for the maintenance of AF, the number of pivoting activation involved in the rotor activation was compared with that not involved in the rotor activation. Further, the activation time involved in the rotor activation was compared with that not involved in the rotor activation. Results: Rotor was identified in 14 (56%) patients (3 paroxysmal and 11 persistent AF patients). Rotor was observed at the septum (8 patients), roof (4 patients), anterior (3 patients) and posterior (1 patient), respectively. The number of rotor activation was 1.5±1.8 times/sec. Total number of pivoting activation was 9.2±6.5 times/sec. The number of pivoting activation involved in the rotor activation was significantly fewer than that not involved in the rotor activation (2.7±3.0 vs. 6.5±5.4 times/sec, p=0.0034). The activation time in which the rotor was observed in the LA occupied 18.5±21.1 % of the total recording intervals. Thus, the percentage of activation time involved in the rotor activation was significantly lower than that not involved in the rotor activation (18.5±21.1% vs. 81.5±21.1%, p<0.0001). Conclusions: Rotor activation was observed outside the PV in only half of AF patients. Further, most of pivoting activations were not involved in the rotor activation and the activation time involved in the rotor activation occupied a limited interval during AF. These suggest that AF after PV isolation was not maintained by the rotor, but was driven by the non-stationary random wave propagation associated with frequent pivoting activations.