Stationary Atrial Fibrillation Properties in the Goat Do Not Entail Stable or Recurrent Conduction Patterns

Abstract

Introduction: Electro-anatomical mapping of the atria is used to identify the substrate of atrial fibrillation (AF). Targeting this substrate by ablation in addition to pulmonary vein ablation did not consistently improve outcome in clinical trials. Generally, the assessment of the substrate is based on short recordings (≤10 s, often even shorter). Thus, targeting the AF substrate assumes spatiotemporal stationarity but little is known about the variability of electrophysiological properties of AF over time.Methods: Atrial fibrillation (AF) was maintained for 3–4 weeks after pericardial electrode implantation in 12 goats. Within a single AF episode 10 consecutive minutes were mapped on the left atrial free wall using a 249-electrode array (2.25 mm inter-electrode spacing). AF cycle length, fractionation index (FI), lateral dissociation, conduction velocity, breakthroughs, and preferentiality of conduction (Pref) were assessed per electrode and AF property maps were constructed. The Pearson correlation coefficient (PCC) between the 10 AF-property maps was calculated to quantify the degree spatiotemporal stationarity of AF properties. Furthermore, the number of waves and presence of re-entrant circuits were analyzed in the first 60-s file. Comparing conduction patterns over time identified recurrent patterns of AF with the use of recurrence plots.Results: The averages of AF property maps were highly stable throughout the ten 60-s-recordings. Spatiotemporal stationarity was high for all 6 property maps, PCC ranged from 0.66 ± 0.11 for Pref to 0.98 ± 0.01 for FI. High stationarity was lost when AF was interrupted for about 1 h. However, the time delay between the recorded files within one episode did not affect PCC. Yet, multiple waves (7.7 ± 2.3) were present simultaneously within the recording area and during 9.2 ± 11% of the analyzed period a re-entrant circuit was observed. Recurrent patterns occurred rarely and were observed in only 3 out of 12 goats.Conclusions: During non-self-terminating AF in the goat, AF properties were stationary. Since this could not be attributed to stable recurrent conduction patterns during AF, it is suggested that AF properties are determined by anatomical and structural properties of the atria even when the conduction patterns are very variable.

A novel framework for noninvasive analysis of short-term atrial activity dynamics during persistent atrial fibrillation

“…More recently, Almeida et al used recurrence plots and recurrence quantification analysis to characterize the dynamics of atrial tissue activations from atrial electrograms of human persistent atrial fibrillation, and showed that this analysis allows discriminate between normal and fractionated atrial electrograms [ 5 ]. van Hunnik et al used recurrent plots to investigate stability of conduction patterns during AF, and found that this poorly correlates with stationarity of AF properties [ 9 ]. All these studies focused on invasive recordings of AA during AF, while our study proposes the use of noninvasive recordings to assess recurrence in AA propagation during AF, and uses this information to improve quantification of AF substrate complexity.…”

A Novel Tool for the Identification and Characterization of Repetitive Patterns in High-Density Contact Mapping of Atrial Fibrillation

“…One-minute recordings of unipolar atrial electrograms were made simultaneously on the right atrial (RA) and left atrial (LA) epicardial wall. Further experimental details can be found in van Hunnik et al (2018) . The study protocol was approved by the local ethics committee and complied with the Dutch and European directives.…”

“…A local source may not always conduct 1:1 to its vicinity but this region is nonetheless expected to exhibit repetitive conduction patterns driven by the source. The presence of repetitive patterns in a region of the atria may furthermore reveal a structure-function relationship at that site, impacted by atrial anatomy (Hansen et al, 2015;van Hunnik et al, 2018) or by structural remodeling associated with AF (Verheule et al, 2010;Maesen et al, 2013). A repetitive pattern may also be the precursor to (spontaneous) termination of AF (Ortiz et al, 1993), or give an indication of the overall state of atrial conduction, i.e., the dynamics of linking of conduction between consecutive activations in different atrial regions (Gerstenfeld et al, 1992).…”

Structural and Functional Properties of Subsidiary Atrial Pacemakers in a Goat Model of Sinus Node Disease

“…The PNA occupies a larger area than the anatomic SAN and could function as a subsidiary pacemaker in pathophysiological conditions ( Chandler et al, 2009 , 2011 ). Although the goat is a well-established and widely used model of atrial arrhythmia ( Wijffels et al, 1995 ; van Hunnik et al, 2018 ), the structure and organization of the SAN in goats are not well known. Data presented here show that the SAN was located in the intercaval region occupying its full thickness from the endocardium to the epicardium and running parallel to the cranial half of the CT as in other smaller animals, like rabbits ( Coppen et al, 1999 ; Zhang et al, 2003 ).…”