Incidence of Distinct Repetitive Atrial Activation Patterns as a Metric for Atrial Fibrillation Complexity

Highly complex and irregular atrial activation patterns during atrial fibrillation $(AF)$ can occasionally be interrupted by repetitive atrial activation patterns (RAAPs). These patterns are thought to be generated by mechanisms that initiate or maintain $AF$ episodes are therefore, might be more diverse in patients with more complex forms of $AF$ We quantified RAAP diversity by the half decay time of the ratio of the unprecedented RAAPs to the total num{###} ${\it ber}$ of RAAPs in a goat model with different durations of sustained $AF[3$ weeks $(3wkAF,\ n=8)$ and 22 weeks $(22wkAF,\ n=8)]$. 32 recordings from left and right atria (LA/RA) of each goat were analyzed. 24 out of 32 curves could be modeled as exponential decay functions with adjusted R-squared $> 0.75$ while others presented more irregular decaying patterns $(3wkAF\ LA:2\ RA:3,22wkAF$ LA: $1 RA:2)$. Half decay rates were significantly shorter in $LAs$ of $3wkAF$ goats $(\delta_{3wkAF}=23.67s\ vs. \delta_{22wkAF}=32.86s,p < 0.05$, Mann-Whitney U-test). There was no significant difference in RA.