Gender-specific reference M-mode values in adults: population-derived values with consideration of the impact of height.

OBJECTIVES: The purpose of this investigation was to derive population-based reference values for M-mode echocardiographic dimensions that can be applied in epidemiologic studies, clinical trials and clinical practice and to determine optimal methods for adjusting these dimensions for body size.
BACKGROUND: M-mode echocardiography remains an important modality for studying cardiovascular disease; this is especially true with regard to detecting target organ damage in systemic hypertension. Most previously published reference values were derived from hospital-based series or relatively small samples and were not gender specific.
METHODS: Using a sample of 288 men and 524 women who were between 20 and 45 years of age and who were free of cardiovascular disease, reference values were derived for end-diastolic and end-systolic left ventricular internal dimensions, left ventricular wall thickness and left atrial dimension. The relations between these dimensions and height, a measure of body size relatively independent of obesity, were investigated using various regression models.
RESULTS: Nomograms for mean and 95th percentile values in men and women were constructed on the basis of linear regression models relating echocardiographic dimensions to height. Adjustment for body surface area greatly attenuated associations between obesity and cardiac dimensions in a separate healthy but less restricted sample of 411 men and 503 women.
CONCLUSIONS: Gender-specific M-mode reference values and nomograms, with mean and 95th percentile values for echocardiographic dimensions as a function of height, are reported. The use of body surface area as means of body size adjustment is called into question.