Influence of fat-free mass on detection of appropriateness of left ventricular mass: the HyperGEN Study.

OBJECTIVES

To evaluate the differences between using height(2.7) or fat-free mass for assessment of the appropriateness of left ventricular mass (LVM) in relation to hemodynamic load, and to evaluate the performance of Doppler as compared with M-mode-derived stroke volume for computation of predicted values of LVM.

DESIGN

Cross-sectional.

SETTING

Population-based.

PARTICIPANTS

We studied 2299 participants from the Hypertension Genetic Epidemiology Network Study (prevalent cardiovascular disease in 342).

OUTCOME MEASURES

Individual predicted values of LVM were generated by equations using sex, stroke work (systolic blood pressure x stroke volume by either Doppler or M-mode) and either height(2.7) or fat-free mass, as measures of body build, in 228 normotensive, non-obese, non-diabetic participants. Observed LVM was divided by the predicted value and evaluated as 'excess of LVM'.

RESULTS

Among 1957 participants without prevalent cardiovascular disease, obese individuals (n = 1008) were slightly younger than non-obese individuals, whereas diabetic participants (n = 294) were slightly older. Excess of LVM was positively related to body mass index (BMI), independently of echocardiographic method and measure of body build, especially when height(2.7) and m-mode stroke work were used, and was greatest in the presence of concentric left ventricular hypertrophy (P < 0.0001). Excess LVM by height(2.7) was progressively greater than that by fat-free mass, as BMI increased (P < 0.0001). In analyses of covariance of association of prevalent cardiovascular disease with age, sex, race, BMI, and excess of LVM (by each method), methods using height(2.7) were more associated with prevalent cardiovascular disease than were methods using fat-free mass (P < 0.02).

CONCLUSIONS

Deviation of LVM from values that compensate hemodynamic load can be similarly identified using different measures of body build and methods to generate stroke work. However, the use of height(2.7) to compute LVM as a percentage of that predicted appears to identify deviations from compensatory values that are independently related to prevalent cardiovascular disease more effectively than does the use of fat-free mass.