Dynamic behavior of rotors during human persistent atrial fibrillation as observed using non-contact mapping

Abstract

Rotors have been related to atrial fibrillation (AF) maintenance. We analyzed the behavior of rotors in persistent AF (persAF) utilizing a novel non-contact methodology and compared this to real time dominant frequency (DF) analysis. 2048 noncontact virtual unipolar atrial electrograms (VEGMs) were collected simultaneously (EnSite Array, St. Jude Medical) from 10 persAF patients (duration: 34 ± 25 months) undergoing left atrial (LA) ablation. After QRST-removal, FFT was used to identify the global DF of the LA (range 4-10 Hz; 1 s time-window; 50 % overlap; highest DF (HDF) (DF -0.25 Hz); up to 20 s/patient). The organization index (OI) was measured and phase was found via Hilbert-transform. Phase singularities (PSs) were tracked and were categorized according to their lifespan into short (lifespan <100 ms) and long lived (rotors) (lifespan >100 ms). A total of 4578 PSs were tracked. 5.05 % (IQR: 2.75 ∼ 30.25 %) of the tracked PSs were long-lived and were observed in 11 % (IQR: 2.75 ∼ 17.5 %) of the windows. The windows with rotors showed significantly higher HDF (mean ± SD, 8.0 ± 0.43 Hz vs 7.71 ± 0.50 Hz, p< 0.0001) and lower OI (0.76 ± 0.04 vs 0.79 ± 0.03, p< 0.0001) when compared with the short-lived PSs windows. During persAF, the LA showed distinct behaviors as characterized by rotors. Often, no rotors were observed during sustained AF and, when present, the rotors continually switched between organized and disorganized behaviors. Long-lived rotors correlated with higher atrial rates. Our results suggest that rotors are not the sole perpetuating mechanism in persAF.