To investigate the clinical roles of mechanical and non-mechanical factors in hypertensive hypertrophy, 125 patients with essential hypertension, 20 with hypertrophic cardiomyopathy (HCM) and 20 with dilated cardiomyopathy (DCM), were studied using echocardiography. The hypertensive patients were separated into 3 groups: those with left ventricular (LV) hypertrophy (H), those without hypertrophy (H(-)) and those with dilatation (D). Group H patients were separated into 3 subgroups: those with subnormal LV end-systolic wall stress (ESS) (HI), those with normal ESS and mild hypertrophy (HIIA), and those with normal ESS and severe hypertrophy (HIIB). The inotropic response to isoproterenol infusion (0.02 microgram/kg/min for 5 min) was measured by the increase of fractional shortening (FS) corrected for the decrease of ESS (delta FS/delta ESS). After antihypertensive treatment for 4.4 +/- 1.7 years, echocardiography was repeated. delta FS/delta ESS was significantly larger in HI and HCM than in HIIA, was significantly larger in HIIA than in HIIB in which it was significantly larger than in D and DCM. After the treatment, LV mass decreased significantly except in HI. In conclusion, hypertensive hearts are regulated by mechanical and non-mechanical factors. Non-mechanical factors, for example the function of beta-adrenergic receptors in myocardium, have a variety of influences on myocardium, causing a broad spectrum of clinical features and courses.