cardiac operation under direct vision

例句：

1. 1.The patient's heart rate was elevated during the procedure.
   在手术过程中，患者的心率升高。
2. 2.The study focused on the cardiovascular system of the human body.
   该研究专注于人体的心血管系统。
3. 3.Cardiac surgery is a complex procedure that requires specialized training.
   心脏手术是一项复杂的程序，需要专门的培训。