Cellular changes in mechanically overloaded heart.

From the ultrastructural aspects of the myocardial cell in different types of heart overloading, several points concerning the adaptation of the myocardial cell were briefly summarized: the respective role of hypertryphy and hyperplasia in heart enlargement, the nature of the myofibrillar changes; the changes in the volume, number and size of mitochondria, and the dependence of the cellular lesions on the severity of the load.