Hypertension research. Echocardiography in the measurement of left ventricular wall mass.

THE purpose of this supplement is to define the current status and future applications of echocardiography in hypertension research. Electrocardiography has long been used in epidemiologic studies of hypertrophy and its regression." More recently, however, mounting evidence of the superior precision, reproducibility, sensitivity, and specificity of echocardiography as a noninvasive tool for measuring left ventricular dimensions and muscle mass has led to its use in the clinical assessment of hypertension. This series of papers focuses on several topics related to the use of echocardiography in hypertension research and in population studies. The techniques of echocardiographic measurement are varied. A consensus has yet to be developed concerning whether to use either M-mode or two-dimensional techniques or both, the appropriate temporal points for end diastole and end systole, the definition of septal and posterior left ventricular wall limits for M-mode and two-dimensional studies, the appropriate views and measurement criteria for twodimensional studies, and the choice of formulas for calculation of left ventricular wall mass." Factors that systematically affect heart size must be considered in the evaluation of left ventricular wall mass. In normal populations, wall thickness and calculated wall mass have been shown to vary with the age, sex, and body surface area of the individual, aside from independent contributions of blood pressure and possibly other hereditary or environmental factors. ~ Regression equations have been developed to define confidence limits of normal left ventricular dimensions and mass based on these variables. ' Agreement on appropriate calculations and limits for normal mass would permit detection of individuals with abnormal left ventricular mass, whose prognosis is expected to be adversely affected. Since precise separation of "normal" from "abnormal" is difficult, using indices of left ventricular mass as continuous variables may be more valuable in understanding the significance of hypertensive cardiac hyper-