Figure 2.

Composition of the normal myocardium and pathological changes of fibrosis. Following myocardial injury, fibroblasts are activated to instigate the transformation from normal myocardium to fibrosis. In interstitial fibrosis, myocyte membranes are not compromised, there is no myocyte death, and a more diffuse pattern of potentially reversible fibrosis ensues. Other more intense forms of injury cause myocyte cell death from the outset, triggering replacement fibrosis seen as focal regions of irreversible cardiac scarring. Interstitial fibrosis can progress to replacement fibrosis in the presence of persistent exposure to myocardial injury. In reality, significant overlap exists between these types but they remain useful when considering the different imaging techniques.