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In cardiology, stunned myocardium is a state when some section of the myocardium (corresponding to area of a major coronary occlusion) shows a form of contractile abnormality. This is a segmental dysfunction which persists for a variable period of time, about two weeks, even after ischemia has been relieved (by for instance angioplasty or coronary artery bypass surgery). In this situation, while myocardial blood flow (MBF) returns to normal, function is still depressed for a variable period of time.
After total ischemia occurs, the myocardium switches immediately form aerobic glycolysis to anaerobic glycolysis resulting in the reduced ability to produce high energy phosphates such as ATP and Creatinine Phosphate. At this point, the lack of the energy and lactate accumulation results in cessation of contraction within 60 seconds of ischemia (i.e. Vessel Occlusion). Subsequent to this is a period of "myocardial stunning," in which reversible ischemic damage is taking place. At approximately 30 minutes after the onset of total ischemia the damage becomes irreversible, thereby ending the phase of myocardial stunning.
Baker C, Rimoldi O, Camici P, Barnes E, Chacon M, Huehns T, Haskard D, Polak J, Hall R (1999). "Repetitive myocardial stunning in pigs is associated with the increased expression of inducible and constitutive nitric oxide synthases.". Cardiovasc Res43 (3): 685–97. doi:10.1016/S0008-6363(99)00149-2. PMID10690340.