PPARGC1A and cardiac arrhythmia: Thus, the results suggested that both long-term HSI and aging contributed to age-related accelerated decline of cardiac contractility and age-related accelerated increase of arrhythmias, and the mechanism may be related to up-regulation of heart salt gene expression and oxidative stress/dTOR pathway, and down-regulation of heart dFOXO/PGC-1α pathway.