Objectives To evaluate whether assessment of appropriateness of left ventricular mass (LVM) adds to the traditional definition of left ventricular hypertrophy (LVH). Design Cross-sectional, relational. Methods Echocardiographic LVH and appropriateness of LVM were studied in 562 subjects (231 normotensive controls, aged 35 +/- 11 years, 142 women; 331 hypertensive patients, aged 47 +/- 11 years, 135 women) classified on the basis of either the presence or the absence of both LVH (LVM index greater than or equal to 51 g/m(2.7)) and inappropriate LVM (LVM > 128% of the value predicted by an equation including age, sex and stroke work). Results Body mass index was comparable in hypertensive patients and controls. Hypertensive patients without LVH but with inappropriate LVM (n = 21) had higher relative wall thickness and total peripheral resistance than all other groups, whereas cardiac output was lower tall P < 0.001). Midwall mechanics was normal with appropriate LVM, independently of presence of LVH, whereas it was depressed in inappropriate LVM, either with or without LVH (both P < 0.0001). There was no substantial difference in ejection fraction among controls and hypertensive groups. Stress-corrected midwall shortening was more closely related to deviation of LVM from the value appropriate for stroke work, body size and gender (r = -0.56, P < 0.0001) than to LVM index (r = -0.26). Conclusions Inappropriate LVM is associated with concentric geometry, high peripheral resistance and depressed wall mechanics. The deviation of LVM from the value appropriate for stroke work. body size and sex correlates with measures of myocardial function better than LVM. (C) 2001 Lippincott Williams & Wilkins.