Abstract: Glucocorticoid (GC) is synthesized by the adrenal gland or in cardiac muscles. GC and mineralocorticoids (MC) have the same affinity for the mineralocorticoid receptor (MR). GC can act on cardiovascular system through binding to MR. GC in the heart is much higher than in the blood. GC activation can be accelerated by oxidative stress, and activated MR can also induce oxidative stress and is involved in myocardial fibrosis, cardiac remodeling and acceleration of calcium ion flow. Elevated serum GC level is an independent prediction factor of increased mortality risk in patients with chronic heart failure. Blocking MR has been reported as one main principle of “upstream” treatment of atrial fibrillation (AF). Elevated GC concentration in some local tissues is a cardiovascular risk factor.