Left Ventricular Wall Stress and Systolic Function in Untreated Primary Hypertension

A noninvasive investigation was undertaken in four blood pressure (BP) groups of untreated 49-year-old men derived by screening a random population sample: normotensive men (n = 20) and subjects with borderline (n = 30), mild (n = 45), or moderate BP elevation (n = 24). We here report the findings regarding left ventricular (LV) wall stress, LV wall thickness, and LV systolic function. Although there was an increase in LV wall thickness with hypertension, the raised BP was not compensated for by a sufficient degree of LV wall thickening to keep wall stress within normal limits in the hypertensive groups. Among a subset of individuals with pronounced increase in wall thickness peak systolic wall stress approached the normal range, but end-systolic wall stress was still high. In spite of high wall stress LV systolic function was normal or supranormal in the hypertensive men. The LV ejection phase indices showed a close inverse correlation with end-systolic wall stress (r = -0.67 to -0.84) in all four BP groups, but no correlation or only a weak correlation with peak systolic wall stress (r = 0.18 to -0.40). As judged from the relationship between end-systolic wall stress and ejection phase indices of LV function in the normotensive controls, all hypertensive groups had higher than expected values for LV ejection phase indices, which indicates an increased myocardial contractility secondary to adrenergic stimulation or to a more efficient contractile machinery in the myocardial cells.