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.