Hypothetical pathways of cardiac myocyte hypertrophy: response to myocardial injury.

The heart is made up of many different cell types, including myocytes, fibroblasts and vascular cells. The cardiac myocyte, although not likely to divide, may respond to gross organ injury by a process of growth or hypertrophy. Cellular hypertrophy, though a normal biological adaptation, has the potential to contribute to the change in the shape and the size of the heart, such as occurs in chronic heart failure. We are now just beginning to understand the signals and early pathways involved in the cardiac myocyte growth response, some of which are reviewed herein.