RYR2 and Paroxysmal atrial fibrillation: From this analysis, it was revealed that ∼70% of RyR2 clusters were within 150 nm of their nearest neighboring cluster in non-AF RAA cardiomyocytes, which was unchanged in either of the AF patient groups (non-AF: 69.78 ± 1.84%; paroxysmal AF: 69.26 ± 1.76%; persistent AF: 70.15 ± 2.90%, respectively; Figure 3D).