CON: Hibernating myocardium: adaptation to ischaemia

Journal of Clinical and Basic Cardiology 2000; 3 (2): 143-144

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Keywords: myokardiale Ischämie,  Ventrikelfunktion,  myocardial ischaemia,  ventricular function

Patients with chronic coronary artery disease frequently have ventricular dysfunction that recovers upon reperfusion. The concept of myocardial hibernation views the observed reduction in contractile function not as the result of an ongoing energetic deficit, but as an adaptive downregulation that serves to maintain myocardial integrity and viability. Experimental studies have indeed demonstrated reduction in regional myocardial function in proportion to the reduction of resting blood flow (perfusion-contraction matching) that recovered upon reperfusion. Furthermore, recovery of energy and substrate metabolism during ongoing ischaemia, the potential for recruitment of inotropic reserve and lack of necrosis are established features of hibernation. Similarly, in most patients, baseline blood flow is reduced in the dysfunctional myocardium. Morphologically, the hibernating myocardium displays features of dedifferentiation, with loss of cardiomyocytes and myofibrils, and of degeneration, with increased interstitial fibrosis. The mechanisms of hibernation, apart from reduced calcium responsiveness, are not clear at present. With the identification of the underlying mechanism(s) of hibernation, it can potentially be recruited and reinforced pharmacologically to delay impending myocardial infarction. J Clin Basic Cardiol 2000; 3: 143-4.