Abstract: Objective： To investigate the curative effect and safety of direct current cardioversion in the treatment of arrhythmia after cardiac surgery. Methods： From January 2014 to March 2018， 144 patients with rapid atrial cardiac arrhythmia which is no response to loading dose of amiodarone after cardiac surgery were selected. According to the different treatment methods， the patients were divided into control group and observation group.The control group continued with amiodarone treatment， and the observation group was treated with direct current cardioversion. Curative effect， complications， mortality and recurrence rate were compared between the two groups of patients. The level of myocardial damage markers in the venous blood was detected at different times. Results： For the 73 patients of the observation group， the effective rate was 84.9%， which was significantly better than the control groups′s 60.6%(P＜0.05).The incidence of complications was 11.3% in the control group， while 15.1% in the observation group， and the mortality was 5.6% vs 0. There was no statistical significance(P＞0.05). The level of myocardial damage markers detected before cardioversion and 24，48，72 h and 1 week after cardioversion in the observation group were statistically analyzed which showed the level of myocardial damage markers increased in different times after cardioversion， and returned to the level before cardioversion with the development of time.Follow-up for half a year， the recurrence rate was 35% in the control group，which was higher than that in the observation group(P＜0.05). Conclusion： Synchronized direct current cardioversion can significantly improve the curative effect of amiodarone in the treatment of rapid atrial cardiac arrhythmia after cardiac surgery. Although it can cause transient myocardial damage， it does not increase the incidence of complications and mortality. It is a safe and effective treatment.