APOE and atrial fibrillation: The recorded mean numbers of viable cells in NP and AF tissues of APOE-knockout rabbits were 10867 ± 753 and 20122 ± 1176 respectively; and in wild-type rabbits the respective mean values amounted to 17834 ± 1262 and 28273 ± 1019 (p < 0.0001).