During coronary artery bypass graft surgery, injury occurs to the heart muscle. Some of this injury is due to the deprivation of oxygen and nutrients to the heart (a process called ischemia) during the surgery itself. The objective of this study is to examine whether remote ischaemic preconditioning (RIPC), in which the application of transient ischemia to the forearm and thigh (through the inflation of blood pressure cuffs placed on the right upper arm and upper thigh) may reduce the injury to the heart muscle sustained during cardiac surgery.