Spatiotemporal Periodicity During Atrial Fibrillation in the Isolated Sheep Heart

Abstract

Reentry in anatomically or functionally determined circuits forms the basis of spatiotemporal periodic activity during AF. The cycle length of sources in the LA determines the dominant peak in the frequency spectra in this experimental model of AF.

An interactive platform to guide catheter ablation in human persistent atrial fibrillation using dominant frequency, organization and phase mapping

“…Although it is believed that DF correlates with the main activation rate representing the local periodic activities, it is important to investigate the relationship between the DF and the remaining frequency components present in the frequency spectrum of the AEGs [10].…”

“…Regularity and organization index have been used to assess the relevance of the DF in the frequency spectrum of AEGs, providing an assessment of the AEG activation organization [8][9][10]. In the present study, RI was defined as the ratio of the area of the DF peak and the total area of the power spectrum (Eq.…”

“…Therefore, AEGs with high DF (HDF) might represent regions with rapid electrical activations and are potential targets for persAF ablation [9]. Additionally, organization index (OI) and regularity index (RI) have been used to estimate the frequency organization of AEGs, which might help in the identification of the underlying activations [8][9][10].…”

Differences in atrial fibrillation properties under vagal nerve stimulation versus atrial tachycardia remodeling

“…Moreover, recent studies of cholinergic AF in the isolated sheep heart demonstrated that high frequency sources in the PV region dominate and drive the fibrillatory activity throughout both atria 39,40 . This and other experimental studies, 17,36,40 has led to the hypothesis that "patients with AF have a focal or reentrant mechanism as the initiating cause of arrhythmia, while perpetuation of AF may depend on the uninterrupted periodic activity of a small number of discrete generators (rotors), most often localized in the LA and established by the interaction of propagating waves with anatomical heterogeneities in the atria" 4,39 . The results of one of the first studies using rapid atrial pacing in dogs to promote AF support such a hypothesis 41 .…”

“…Furthermore, experimental work demonstrated the existence of spiral waves during AF with optical 36 and high density conventional mapping 24,37 . A mathematical model of atrial activity with representations of atrial ionic and conduction properties in a 2-dimensional grid indicated also a spiral wave activity during AF 38 .…”