Earliest histological change in MI-

The microscopic appearance also undergoes a characteristic sequence of changes Typical features of coagulative necrosis become detectable within 4 to 12 hours of infarction. "Wavy fibers" also can be present at the edges of an infarct; these reflect the stretching and buckling of noncontractile dead fibers. Sublethal ischemia can also induce intracellular myocyte vacuolization; such myocytes are ble but frequently are poorly contractile. (Robbins Basic Pathology,9th edition,pg no.383)