Metabolic aspects of hibernating myocardium

Myocardial hibernation describes the clinical entity of a dysfunctional region of myocardium with reduced flow that shows improvement in function after flow is restored. It is postulated that despite the reduced flow, metabolic activity is sufficient to prevent tissue necrosis. Experimental work in animals supports this. A moderate reduction in flow to a region of the left ventricle in pigs initially results in the typical metabolic picture of ischemia: ATP and PCr fall and anaerobic metabolism is present. However, over the next hour, a hypometabolic response occurs that eliminates almost all metabolic findings of ischemia despite ongoing flow reductions. This appears to be an actively and tightly regulated response. The reduction in systolic function is an important part of the hypometabolic state, but cannot fully account for the downregulation of energy use.