Classification of hypertrophied hearts in essential hypertension: evaluation by left ventricular wall stress and adrenergic responses.

Left ventricular mass, fractional shortening, and end systolic wall stress (mechanical indices) measured by echocardiography and the response of fractional shortening and end systolic wall stress to the infusion of isoproterenol (0.02 microgram/kg/min for 5 min) (a non-mechanical index) were studied in 57 patients (mean (SD) age 49(8)) with essential hypertension. Nineteen patients had subnormal end systolic wall stress (group 1), 25 patients had normal end systolic wall stress and slightly increased left ventricular mass (group 2A), and 13 patients had normal end systolic wall stress and considerably increased left ventricular mass (group 2B). Plasma noradrenaline concentration was higher in group 2B than in the other groups. When end systolic wall stress was greater than 12 g/cm2 this variable showed a significant inverse linear relation with fractional shortening before isoproterenol infusion. The inotropic response to isoproterenol was measured as the increase of fractional shortening corrected for the decrease of end systolic wall stress (delta fractional shortening/--delta end systolic wall stress). The mean (SD) change in delta fractional shortening/--delta end systolic wall stress was significantly larger in group 1 (1.40 (0.60) cm2/g) than in group 2A (0.85 (0.39) cm2/g), and was significantly larger in group 2A than in group 2B (0.56 (0.15) cm2/g). In patients with hypertensive hypertrophy with subnormal end systolic wall stress (inappropriate hypertrophy) the beta adrenergic response is increased; in hypertensive hypertrophy with normal end systolic wall stress (appropriate hypertrophy), however, it is normal, or becomes reduced as plasma noradrenaline increases.