Fig. 4.

Atrial fibrillatio propagation pattern. AF complexity was addressed using HD contact mapping in an open-chest study. a Atrial fibrillatory cycle length, b fractionation index, c waves per cycle, and d maximum dissociation, a measure of the largest dissociation from an activation point. In the untrained group, all of these variables were significantly different between the right and left atria. This difference was attenuated in the trained group. Data is presented as mean ± standard deviation, and for statistical analysis, multiple unpaired Mann–Whitney (a–c) and t test (d) were performed followed by the Holm-Sidák post hoc analysis for correction. Completely untrained horses are presented as red circles. AFCL, atrial fibrillation cycle length; LA, left atrium; RA, right atrium; U, untrained; T, trained