Increased understanding of the effects of ischemia on the myocardium has led to advances in the field of myocardial protection during cardiac surgery. These advances, combined with improved surgical techniques, have contributed to the success of cardiac surgery and the ability to revascularize high-risk populations. The most common technique used to protect the myocardium is cardioplegia administration. Although it is the surgeon’s responsibility to decide on solution composition, temperature, and direction of delivery it is the bedside nurse who monitors the patient after surgery. Armed with knowledge about the essential concepts of myocardial protection, the critical care nurse will be prepared to care adequately for the patient after cardiac surgery.