Background:
The prevalence of cardiovascular diseases among people in industrialized and developing countries are increasing. A look at recent WHO statistics suggests that these diseases account for 23% of global mortality rates, which make up a significant proportion in comparison with other causes of mortality. It is sate to be said that cardiovascular diseases cause problems for people and cause worries in the community, including lack of presence at work, high cost of surgery and drugs, disability and other cases. Evidence suggests that coronary artery disease is associated with anxiety and depression, sleep disorders, severe fatigue, and emotional complaints, since the body and mind are not separate.

Objectives:
By providing the necessary knowledge to patients, to a great extent, their mental problems can be prevented.

Materials and Methods:
This is an analytical study that evaluates the effect of preoperative training on depression in patients undergoing cardiac surgery in Shahid Modares Hospital. This study was performed on 80 patients undergoing cardiac surgery who were randomly divided into two groups of control and test. Before operation (surgery), the depression of the two groups was measured by Beck’s standard test. Then, the necessary training was given to the case (test) group. Then one month after the operation (surgery), the depression of the two groups was again measured and compared. The data collection tool was Beck’s standard test, which grading scale indicates 7-0, mild depression, 8-14, moderate depression, and 15-26, severe depression.

Findings:
The results of this study indicate that the training reduced the severe depression by 50% in the case group, but did not affect the mild to moderate depression. According to (p <0.001), there is a significant difference between depression two groups of control and case (test), and severe depression in the case group has been reduced by half. In addition, the research hypothesis was confirmed with 95% confidence. According to the above findings, it can be said that training not only reduces the physical problems of individuals, but also affects the mental and psychological problems of individuals.

Conclusion:
By communicating with patients and giving the necessary training in special wards, especially cardiac surgery, they can be more hopeful for their lives and their depression can be reduced and their recovery facilitated.