Evaluation of left ventricular hypertrophy by M-mode echocardiography in patients and experimental animals.

In validation studies, M-mode echocardiography has been shown to measure left ventricular (LV) mass with reasonable accuracy (r > or = .90 v necropsy measurements) in species ranging in body size from humans to rats. The sensitivity of antemortem echocardiography for the detection of necropsy LV hypertrophy as a qualitative abnormality has also been high (85% to 100%). Increased LV mass is strongly related to both increased blood pressure and to being overweight or to other causes of increased cardiac volume work. LV mass is also increased in the presence of exaggerated blood pressure responses to everyday activity, high sodium intake and blood viscosity, and genetic factors predisposing to hypertension. Indexation of LV mass by body surface area or height has advantages for the detection of hypertrophy related to hypertension or obesity. Indexation of LV mass for the power of its relation to height (2.7) revealed by analysis of growth (allometric) relations may accomplish both these goals. Recent research indicates that the level of LV mass measured by M-mode echocardiography is a stronger predictor of subsequent morbid events and death than blood pressure or other conventional risk factors except age. Preliminary findings of close relations between LV mass and arterial disease and between the change in LV mass during antihypertensive treatment and subsequent events contribute to explaining the strong predictive value of LV mass.