Myocardial stunning and hibernation in clinical practice.

Myocardial stunning and hibernation are both clinically important causes of myocardial dysfunction and are caused by episodes of myocardial ischaemia. Stunning tends to occur acutely and may produce transient but clinically important reductions in left ventricular function in the setting of myocardial infarction, post coronary artery bypass grafting and even following episodes of effort induced angina. Hibernation refers to a chronic down-regulation of myocardial function in response to chronic myocardial ischaemia. Hibernating myocardium may be present in up to 50% of patients with significantly impaired left ventricular function and evidence of heart failure. Importantly, both these entities can be either prevented or ameliorated by preventing or lessening ischaemic burden. There is also evidence that there may be an overlap between these two entities and that hibernating myocardium may result from repeated episodes of myocardial ischaemia causing chronic stunning.