A method for detecting changes in left ventricular mass during variations in filling volume.

Abstract

Two-dimensional echocardiography has been useful for measuring changes in left ventricular mass (LVM) at constant left ventricular end-diastolic volume (LVEDV). Two-dimensional echocardiographic measurement of LVM changes during variations in LVEDV requires definition of the LVM/LVEDV relation because two-dimensional echocardiographic measurements could be affected by asymmetrical redistribution of LVM. Echocardiography data were recorded during caval occlusions in pigs (n = 6). Results confirm that A(M) (left ventricular [LV] short-axis cross-sectional [SACS] wall thickness area), was inversely related to AL (LV SACS lumen area), the average relation being A(M) = -0.33 AL + 20 (r = 0.82 +/- 0.05 [SE]). In addition, we developed a model that computes normal relation between LV SACS wall thickness area (AMc) and LV SACS lumen area (ALc) over a physiologic range of LVEDVs based on a single end-diastolic two-dimensional echocardiographic SACS image. Each computed relation corresponds uniquely to an LVM (LVMc). Theoretically, a difference between AMc/ALc relation before an intervention and the computed relation after the intervention would indicate a change in LVM. To test the utility of this model, edema was induced in a second group of pigs (n = 6) by coronary hemodilution. Two conditions were tested: pre-edema and edema. Serial AMc/ALc and LVMc were computed. Pre-edema and edema AMc were compared at matched LV SACS end-diastolic areas (ALc = 15 cm2). Results showed a significant increase in LVMc (two-tailed p value < 0.05), as observed by two-dimensional echocardiography. We conclude that the A(M) and AL are inversely related. This relation is useful for detecting alterations in LVM during variations in LVEDV.