Spatially Distributed Dominant Excitation Frequencies Reveal Hidden Organization in Atrial Fibrillation in the Langendorff‐Perfused Sheep Heart

Abstract

In this model, AF is characterized by multiple domains with distinct DFs on the atrial epicardium. The decrease in domain area with increased rate suggests that AF results from high-frequency impulses that undergo spectral transformations. The LA is generally faster and more organized than the RA, suggesting that the sources for the impulses are localized to the LA.

Left-to-Right Gradient of Atrial Frequencies During Acute Atrial Fibrillation in the Isolated Sheep Heart

“…These DFs were presented as a map that described their spatial distribution. 7,16 The estimation of the power spectrum was obtained by the method of Welch. 16,17 Briefly, the time series were subdivided into 2 partially overlapping segments.…”

“…7,16 The estimation of the power spectrum was obtained by the method of Welch. 16,17 Briefly, the time series were subdivided into 2 partially overlapping segments. The power spectra of each 2.13-second-long segment were obtained via FFT, and these were averaged and normalized to their total power.…”

Is there a role for remodeled connexins in AF? No simple answers

“…The concept is supported by the finding of circumscribed regions initiating impulses at high frequencies with a gradient of decreasing frequencies distant from the highest frequency region [25,26]. Mapping from the high frequency region has shown centrifugal spread and in some instances AF cycle length has prolonged during radiofrequency delivery to the high frequency region (27).…”

Current Status and Future of Cardiac Mapping in Atrial Fibrillation

“…Experimental studies using high-resolution optical mapping of impulse propagation during AF in the isolated sheep heart demonstrate that acetylcholine (Ach) dose-dependent reentrant sources in the left atrium can drive the fibrillatory activity throughout both atria. Using phase representation of the local impulse kinetics, Berenfeld et al [73][74] establish that rotors can arise from unidirectional blocks of propagation at functional obstacles. Further spatiotemporal tracking of the wavebreak sites identifies a functional isthmus in the wake of such an obstacle whose minimal width supporting a figure-of-eight reentry substance is about 4 mm.…”