- Poster presentation
- Open Access
The relationship of left ventricular function to infarct surface area and volume
© Ramsey et al; licensee BioMed Central Ltd. 2009
- Published: 28 January 2009
- Left Ventricular Function
- Left Ventricular Mass
- Volume Shrinkage
- Impaired Left Ventricular Function
- Free Open Source
To examine the relationship between left ventricular (LV) myocardial function and myocardial infarct (MI) surface area and volume.
Delayed-enhancement MRI (DE-MRI) has been used successfully to describe the relationship between the volume of scar tissue and LV function . Due to volume shrinkage of hyperenhanced tissue over time, DE-MRI derived infarct surface area (iSA) and the iSA to infarct volume ratio (iSA/V) may provide more stable indices of the extent of infarction than does scar volume and may better predict LV functional impairment.
LV function was assessed using CIM software , which provided the following global measurements: LV mass, LVEF, LV end-diastolic volume (EDV), and LV end-systolic volume (ESV). CIM also provided segmental data based on a 16 segment LV model: myocardial thickening (peak thickness – minimum thickness), EDV, ESV, and EF. Infarct and LV mass were calculated from their respective volumes assuming a constant density of 1.04 g/ml. Mid-ventricular segments that visually contained greater than 50% hyper-enhancement on DE-MRI were considered infarcted. Segments which were non-infarcted and not adjacent to infarcted segments were considered remote. Statistical comparisons between infarct and remote regions were made using a paired, two-tailed student's t-test. For linear relationship comparisons, the standard error of the estimate was calculated to examine goodness-of-fit.
Impaired LV function is strongly related to infarct surface area. Relative infarct mass may underestimate the extent of damage post-MI because of thinning of infarcted myocardium during remodeling. Infarct surface area is less affected by volume shrinkage, and may be more stable over time than infarct mass in measuring the loss of functioning myocardium.
A greater decrease in LV wall thickening is associated with a larger relative infarct mass and surface area but a smaller iSA/V. A transmural increase in infarct size may increase infarct volume with little change in iSA. Infarct transmurality greater than 50% is associated with severe loss of myocardial function and mortality . Thus, iSA/V can provide an objective quantitative index of transmurality, superior to relative infarct mass for predicting decrease in myocardial function.
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