Gross sequence of Changes in MI Time Predominant finding 0 to 18 hours No gross changes 18 to 24 hours Vague pallor and softening 1 to 7 days Yellow scar 7 to 28 days Central scar formation with red border Months Thick white Firm scar formation Microscopic changes in MI Survival Time Predominant Finding 1-4 hours Wavy myocyte fibers, contraction bands 4-24 hours Coagulative necrosis 1 to 3 days Neutrophil infiltration 3 to 7 days Macrophage infiltration 7 to 28 days Granulation tissue Months Fibrotic scar
Science progresses by questioning the existing dogmas.