ROCK1 and atrial fibrillation: Similarly, immunofluorescence study revealed a significant co-localization and juxtaposition of the expression of ROCK1 and the expression of cleaved caspase-3 in the left atrial myocytes both in the MR AF group (Pearson’s coefficient = 0.65 ± 0.03) and the MR sinus group (Pearson’s coefficient = 0.65 ± 0.03) (Fig. 8).