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

Area of Science:

• Cardiovascular Physiology
• Echocardiography
• Biomedical Engineering

Background:

• Two-dimensional echocardiography (2DE) measures left ventricular mass (LVM) at constant volume.
• Assessing LVM changes during volume variations requires understanding the LVM/LVEDV relationship.
• 2DE measurements can be influenced by asymmetrical LVM redistribution.

Purpose of the Study:

• To define the relationship between left ventricular short-axis cross-sectional wall thickness area (A(M)) and lumen area (A(L)).
• To develop a model for computing normal A(M)/A(L) relations across physiological left ventricular end-diastolic volumes (LVEDVs).
• To validate the model's utility in detecting LVM alterations using 2DE.

Main Methods:

• Echocardiography data collected during caval occlusions in pigs (n=6).
• Developed a model to compute normal A(M)/A(L) relations (A(Mc)/A(Lc)) from a single end-diastolic 2DE image.
• Induced edema in pigs (n=6) via coronary hemodilution to test the model under pre-edema and edema conditions.

Main Results:

• Confirmed an inverse relationship between A(M) and A(L) (A(M) = -0.33 A(L) + 20, r=0.82).
• The model uniquely computes LVM (LVMc) for each A(Mc)/A(Lc) relation.
• Demonstrated a significant increase in LVMc during induced edema compared to pre-edema at matched LVEDV.

Conclusions:

• The inverse relationship between A(M) and A(L) is confirmed.
• The developed model accurately detects changes in LVM during LVEDV variations.
• This approach enhances the utility of 2DE for assessing cardiac remodeling.