The role of the heart in hypertension has finally emerged as a major issue of cardiovascular concern by the clinician, physiologist, pharmacologist, biochemist, and molecular biologist. This discussion provides an overview of the present state of knowledge and current areas of investigation in this active area of broad interest. Generally, these relate to: the active participation of the heart (e.g. hemodynamic, humoral, autocrine/paracrine); the adaptive response of the heart (i.e. hemodynamic); non-hemodynamic relationships (vis-a-vis, age, race, gender, humoral, coexistent disease); and current thoughts on mechanisms of so-called regression of left ventricular hypertrophy. Several antihypertensive classes of compounds are characterized by decreasing cardiac mass and left ventricular wall thicknesses. The angiotensin converting enzyme inhibitors are included among these agents; their physiological effects in producing "regression" are under active study as are the mechanisms responsible for these changes. These concerns are no longer of incidental or theoretical interest but have major impact on selection of antihypertensive therapy and the management of the patient with hypertension. Thus, the heart may participate actively in the pathogenesis and maintenance of the disease; it adapts to the vascular disease hemodynamically; but in this regard the response has both positive beneficial concerns as well as negative implications as an independent risk factor. These latter concerns should be explored in great depth before conclusions are made with respect to the long-term implications of antihypertensive therapy on the heart.