Myocardial ischaemia

Myocardial ischaemia occurs frequently during the peri-operative period and is associated with major cardiac events in patients with silent or overt coronary artery disease. Often caused by an imbalance between excessive oxygen demand and limited oxygen supply, ischaemia may also occur as a result of endothelial dysfunction in diseased coronary arteries. Myocardial ischaemia impairs systolic and diastolic ventricular function and facilitates the development of arrhythmias. The effects of myocardial ischaemia may persist after reperfusion (myocardial stunning). When ischaemia is chronic, down-regulation of ventricular function (myocardial hibernation) allows the heart to recover after reperfusion. Peri-operatively myocardial ischaemia is most frequently silent and is caused by haemodynamic aberrations, coagulation disorders and/or hypoxaemia. Prevention of peri-operative silent ischaemia is necessary in order to reduce the risk of adverse cardiac events.