Fig. 5: Identification of atrial myocardial damage during atrial fibrillation.

a Quantification and comparisons of high-sensitivity TroponinT (hs-TnT) levels in plasma samples of atrial fibrillation (AF) animals and sham-operated controls over the follow-up. Statistical significance was tested with 2-way ANOVA followed by the Šídák’s multiple comparisons test (p = 0.027). b Representative images and quantification of Caspase3 staining in left atrial (LA) and left ventricular (LV) samples of animals with persistent AF (PsAF). Caspase3+ immunoreactivity was visualized with DAB stain (in brown, indicated with black arrows) and cell nuclei were visualized with hematoxylin (in blue). A two-tailed paired Student’s t test was used to assess differences. c Sample Picrosirius red staining and interstitial fibrosis quantification in LV samples of AF animals and sham-operated controls. A two-tailed unpaired Student’s t test was used to assess differences. d Detection and quantification of apoptosis by TUNEL assay in LA samples from AF animals and sham-operated controls. Samples were counterstained for nuclei (blue, DAPI) and wheat germ agglutinin (green, WGA). White arrows indicate atrial cardiomyocytes with TUNEL+ nuclei. The Mann–Whitney test was used to assess differences. e Representative Western blots (upper) showing the expression of BAX against GAPDH in LA and LV samples from AF animals and sham-operated controls. Quantification and comparisons of BAX expression relative to GAPDH. Data are displayed as individual values with median and interquartile range. Mann–Whitney’s and Wilcoxon’s tests were used to assess statistical significance between groups and anatomical regions, respectively. Source data are provided as a Source Data file.