DIONYSOS is a short-term, randomized, double-blind, parallel controlled trial study comparing the effectiveness and safety of amiodarone and dronedarone. The study found that amiodarone was superior to dronedarone in reducing recurrence of atrial fibrillation in patients with persistent atrial fibrillation, but dronedarone was better tolerated.The ATHENA study showed that dronedarone reduced death and hospitalization for cardiovascular disease causes and had a lower incidence of stroke compared to the placebo group. In patients with decompensated heart failure and impaired left ventricular function, dronedarone may increase mortality, which may be associated with further progression of heart failure. Therefore, in patients with impaired left ventricular function, recently decompensated heart failure or cardiac function class IV (NYHA classification), the use of dronedarone is harmful. Huang Shen, Cardiac Arrhythmia Treatment Center, Guangdong Provincial Hospital of Traditional Chinese Medicine