Without treatment Pak1 cKO mice demonstrated significantly high incidences of atrial arrhythmias than Pak1fl/fl control mice (p < 0.001), but not in Pak1fl/fl control mice (0 out of 43; figure 1aa), while atrial arrhythmias including atrial bigeminy, multi atrial ectopic beats, and atrial tachycardia (1 out of 28) episodes were detected in Pak1 cKO mice (1, 1, and 5 out of 28 respectively) from resting surface ECG (figure 1ab). This evidence concerns the gene PAK1 and atrial tachycardia.