Intraoperative echocardiography: interpretation of changes in left ventricular wall thickness

Quantitative two-dimensional echocardiography (Q2-DE) may be used to detect intraoperative changes in left ventricular (LV) mass (M) and wall thickness (h). Potential causes of change in h include physiological redistribution of myocardium, myocardial edema, reactive hyperemia, and intramyocardial hemorrhage. Changes in h, in the absence of changes in LV shape and volume, generally indicate increased LVM. When changes in h are accompanied by changes in shape or volume, changes in LVM can only be detected by mathematical modeling, unless the direction of the observed changes is opposite that expected with physiological redistribution. Histological observations essential to understanding current mathematical models are presented and related to the inherent solid geometry. Technical considerations in determination of LV mass by Q2-DE are discussed. New procedures that alter LV volume and geometry, such as the Batista operation, defy modeling by conventional methods. Modeling techniques that allow an experimental approach to understanding LVM and h under such conditions are presented.