Symptomatic congestive heart failure is the culmination of a process that evolves over many years. The long preclinical, or ''incubation,'' period is the setting for a broad range of so-called local activities, including those involved in myocardial remodeling. Growth factors, cytokines, and vasoactive substances are central to this dynamic process, as are different populations of myocardial and circulating cells. The effects of angiotensin, endothelin, endothelium-derived relaxing factor, transforming growth factor-beta, and platelet-derived growth factor on myocardial structure, contractile function, and blood flow are outlined. The mechanisms involved in the activation of interleukin-1 and of tumor necrosis factor are examined within the context of the pathologic process.